The Queen's Indian Defense for Black – the whole course to read – Learning studio

Starting position after 1.d4 Nf6 2.c4 e6 3.Nf3 b6

The Queen's Indian is one of the most solid answers to 1.d4 when White avoids the Nimzo-Indian with 3.Nf3. With 3...b6 Black prepares the fianchetto: from b7 the bishop controls the square e4 and the long diagonal; often it also goes to a6 and attacks c4. Black fights for the centre not with pawns but with pieces – d5 or c5 come later. Against the main road 4.g3 the course plays 4...Ba6, against the Petrosian Variation 4.a3 the set-up with 4...Bb7 and 5...d5. Stockfish sees White only slightly ahead in all lines, by one or two tenths – a very good value for Black. The course rests on 18,668 games. White's other roads are 4.Nc3 and 4.e3.

The ideas

The bishop on b7 controls e4 – as long as White cannot play e4, Black has enough in the centre.
Against White's fianchetto, Ba6 attacks the pawn on c4 and forces White into b3, Qa4, Nbd2 or Qb3.
After b3, Bb4 uses the weakness on c3: White's bishop has to go to d2 and stands in the way there.
The levers c5 and d5 come once the pieces are out – often with c6 and d5 as a firm centre.
If White gives the bishop on f6, recapture with a piece – taking back with the g-pawn tears open the king in several lines.

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Chapter 1: 4.g3

Line 1: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5 9.Ne5 Nfd7 10.Nxd7 Nxd7 11.Nd2 O-O 12.O-O Rc8 13.e4 b5 14.Re1 dxe4 15.Bxe4 bxc4 16.bxc4 c5 17.d5 exd5 18.Bxd5 Bf6

4.g3: White's main road, in four games out of ten: the Fianchetto Variation. The bishop is heading for g2 to work on the long diagonal your bishop wants too. Stockfish sees 4.g3 (+0.18) and 4.a3 (+0.17) as equal, 4.Nc3 (+0.05) a little behind.
4…Ba6: The Nimzowitsch Variation: the bishop attacks c4 at once, before White can guard it with Bg2. Stockfish sees 4...Ba6 and 4...Bb7 as equal (both +0.18) – the players choose Ba6 in nine games out of ten, and White has to look after c4 at once.
5.b3: The quiet reply: the b-pawn guards c4. Stockfish sees 5.b3 and 5.Nbd2 as equal (+0.14), 5.Qc2 (+0.1) just behind. The drawback: the diagonal a1–h8 is now open to Bb4.
5…Bb4: With check you use the weakness of c3: White's bishop has to go to d2, where it has little to do. Stockfish chooses 5...Bb4 (+0.19) just ahead of 5...d5 (+0.22).
6.Bd2: 6.Bd2 offers a bishop trade – after bishop takes on d2 the queen on d2 would cover c4 and d4, so you prefer to retreat.
6…Be7: The bishop retreats – White's bishop now stands worse on d2 than on c1, because it takes the square from the queen. Stockfish chooses 6...Be7 (+0.19) ahead of 6...c5 (+0.22). The players play it in almost every game.
7.Bg2: White completes the fianchetto. Stockfish thinks 7.Bg2 (+0.14) is the most accurate, ahead of 7.Nc3 (+0.09) and 7.Bf4 (0).
7…c6: The typical plan: c6 and d5 build a firm centre, and the bishop on a6 keeps pressing on c4. Stockfish had 7...d5 (+0.12) just ahead; 7...c6 gives away only six hundredths and is the move of seven out of ten players.
8.Bc3: The bishop goes to c3 onto the long diagonal: it covers d4 and faces your kingside should you play c5.
8…d5: d5 is the core of the set-up with c6: you put a firm pawn in the centre and keep c4 under pressure.
9.Ne5: The knight jumps to e5 and opens the long diagonal for the bishop on g2 – White aims at c6 and a8.
9…Nfd7: With Nfd7 you offer a knight trade: without the knight on e5 White loses the pressure against c6.
10.Nxd7: White trades on d7 – the position gets quieter, fewer pieces remain.
10…Nxd7: You recapture with the knight; it stands well on d7 and supports c5 or e5.
11.Nd2: The knight goes to d2 and covers c4 – so White can prepare e4 in peace.
11…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
12.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
12…Rc8: The rook goes to c8 behind your pawn on c6 – it prepares c5, the second freeing move.
13.e4: e4 is White's plan in this set-up: it attacks d5 and wants a big pawn centre.
13…b5: Stockfish would have chosen 13...c5 (+0.08) here; 13...b5 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
14.Re1: The rook goes to e1 and supports e4 – White prepares the central push.
14…dxe4: Stockfish would have chosen 14...dxc4 (+0.12) here; 14...dxe4 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
15.Bxe4: White recaptures with the bishop; it stands strongly on e4 and eyes h7.
15…bxc4: You take on c4 – White must recapture, and the b-file opens for your rook.
16.bxc4: White recaptures with the pawn; the pawn on c4 is now a target for your bishop on a6.
16…c5: c5 attacks d4: you use the fact that the bishop on c3 and the pawn on d4 stand on the same diagonal.
17.d5: 17.d5 pushes on before you can trade on d4 – White gets a passed pawn in the centre.
17…exd5: Watch out: the exact move counts here. Stockfish rates 17...exd5 (+0.22) clearly ahead of 17...Bf6 (+0.63).
18.Bxd5: White recaptures with the bishop; it stands in the centre, but you have the pressure on c4.
18…Bf6: The bishop goes to f6 and trades the bishop on c3 – after that the pawn on c4 is weak. Stockfish: level (+0.19).

Line 2: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5 9.Ne5 Nfd7 10.Nxd7 Nxd7 11.Nd2 O-O 12.O-O Rc8 13.e4 b5 14.Re1 dxe4 15.Nxe4 bxc4 16.Qe2 c5

up to 14…dxe4 as line 1

15.Nxe4: White recaptures with the knight; it stands centrally on e4 and eyes d6.
15…bxc4: Watch out: the exact move counts here. Stockfish rates 15...bxc4 (+0.18) clearly ahead of 15...Nf6 (+1.08).
16.Qe2: The queen goes to e2 and wins back the pawn on c4.
16…c5: 16...c5 attacks d4 and opens your bishop's diagonal – a good counter. Stockfish: level (+0.16).

Line 3: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5 9.Ne5 Nfd7 10.Nxd7 Nxd7 11.Nd2 O-O 12.O-O Rc8 13.Re1 f5 14.a4 Nf6 15.a5 b5

up to 12…Rc8 as line 2

13.Re1: The rook goes to e1 and supports e4 against your pawn on d5.
13…f5: Stockfish would have chosen 13...c5 (+0.06) here; 13...f5 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
14.a4: 14.a4 gains space on the queenside and threatens a5 against your pawn on b6.
14…Nf6: The knight returns to f6 and keeps e4 under control.
15.a5: 15.a5 attacks your pawn on b6 and wants to open the a-file.
15…b5: 15...b5 avoids the trade and attacks c4. Stockfish: level (+0.16).

Line 4: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5 9.Ne5 Nfd7 10.Nxd7 Nxd7 11.Nd2 O-O 12.O-O Rc8 13.Re1 f5 14.Rc1 Nf6 15.Bb2 h6

up to 13…f5 as line 3

14.Rc1: The rook goes to c1 and covers the pawn on c4 against your bishop on a6.
14…Nf6: The knight returns to f6 and keeps a grip on e4.
15.Bb2: The bishop goes to b2 and keeps the diagonal a1–h8.
15…h6: 15...h6 gives your king air – the position is solid. Stockfish: level (+0.19).

Line 5: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5 9.Nbd2 Nbd7 10.O-O O-O 11.Re1 c5 12.e4 dxe4 13.Nxe4 Bb7 14.Nfg5 cxd4 15.Bxd4 Qc7 16.Nxf6 Bxf6 17.Bxb7 Qxb7 18.Ne4 Bxd4

up to 8…d5 as line 4

9.Nbd2: The knight goes to d2 and covers c4 and e4 – it prepares the push e4.
9…Nbd7: The knight goes to d7 and supports the freeing moves c5 and e5.
10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
10…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
11.Re1: The rook goes to e1 and supports e4 – White prepares the central push.
11…c5: c5 attacks d4: you use the fact that the bishop on c3 and the pawn on d4 stand on the same diagonal.
12.e4: e4 is White's plan in this set-up: it attacks d5 and wants a big pawn centre.
12…dxe4: You take on e4 and open the long diagonal for your bishop.
13.Nxe4: White recaptures with the knight; it stands centrally and attacks your knight on f6.
13…Bb7: The bishop goes back to b7 onto the long diagonal and attacks the knight on e4.
14.Nfg5: The knight goes to g5 and eyes e6 and h7 – White looks for attacking chances.
14…cxd4: You trade on d4 and open the long diagonal – your bishop on b7 now looks all the way to g2.
15.Bxd4: White recaptures with the bishop; it stands strongly on d4.
15…Qc7: The queen goes to c7 and connects the rooks.
16.Nxf6: White trades on f6 and takes away a defender of your king.
16…Bxf6: Watch out: the exact move counts here. Stockfish rates 16...Bxf6 (+0.06) clearly ahead of 16...Nxf6 (+0.65).
17.Bxb7: White trades the light bishops – the long diagonal is quiet.
17…Qxb7: Watch out: the exact move counts here. Stockfish rates 17...Qxb7 (+0.09) clearly ahead of 17...Bxd4 (+0.84).
18.Ne4: The knight attacks your bishop on f6 and wants to trade the last pair of bishops.
18…Bxd4: You trade the dark bishops – the position is level. Stockfish: level (+0.04).

Line 6: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5 9.Nbd2 Nbd7 10.O-O O-O 11.Re1 c5 12.e4 dxe4 13.Nxe4 Bb7 14.Nfg5 cxd4 15.Bxd4 Qc7 16.Nxf6 Bxf6 17.Bxb7 Qxb7 18.Qf3 Rfb8

up to 17…Qxb7 as line 5

18.Qf3: The queen goes to f3 and offers a queen trade.
18…Rfb8: The rook goes to b8 onto the half-open b-file and presses on b3. Stockfish: level (0).

Line 7: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5 9.Nbd2 Nbd7 10.O-O O-O 11.Re1 c5 12.e4 dxe4 13.Nxe4 Bb7 14.Nxf6 Bxf6 15.Qd2 Qc7 16.Rad1 Rad8

up to 13…Bb7 as line 6

14.Nxf6: White trades on f6 and simplifies the centre.
14…Bxf6: You recapture with the bishop; it presses on d4.
15.Qd2: The queen goes to d2 and covers d4 – she also connects the rooks.
15…Qc7: The queen goes to c7 and connects the rooks.
16.Rad1: The rook goes to d1 and supports the pawn on d4.
16…Rad8: The rook goes to d8 and increases the pressure on d4. Stockfish: level (+0.12).

Line 8: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5 9.Nbd2 Nbd7 10.O-O O-O 11.Re1 c5 12.e4 dxe4 13.Nxe4 Bb7 14.Ned2 Rc8 15.Qe2 cxd4

up to 13…Bb7 as line 7

14.Ned2: The knight retreats to d2 and covers c4.
14…Rc8: The rook goes to the c-file and supports c5.
15.Qe2: The queen goes to e2 and connects the rooks.
15…cxd4: You trade on d4 and open the c-file for your rook on c8. Stockfish: level (+0.05).

Line 9: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5 9.Nbd2 Nbd7 10.O-O O-O 11.Re1 c5 12.e4 dxe4 13.Ng5 cxd4 14.Bxd4 Qc7 15.Ngxe4 Rad8

up to 12…dxe4 as line 8

13.Ng5: The knight goes to g5 and attacks your pawn on e4.
13…cxd4: You trade on d4 and open the position while your pawn on e4 still stands.
14.Bxd4: White recaptures with the bishop; it stands strongly in the centre.
14…Qc7: The queen goes to c7, covers e5 and eyes the c-file.
15.Ngxe4: White wins back the pawn on e4 – material is level again.
15…Rad8: The rook goes to d8 and eyes the bishop on d4. Stockfish: level (+0.14).

Line 10: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5 9.Nbd2 Nbd7 10.O-O O-O 11.Re1 c5 12.cxd5 Nxd5 13.Bb2 Rc8 14.Rc1 b5 15.Bf1 cxd4

up to 11…c5 as line 9

12.cxd5: White trades on d5 and opens the diagonal of his bishop on g2.
12…Nxd5: You recapture with the knight and attack the bishop on c3.
13.Bb2: The bishop retreats to b2 and stays on the long diagonal.
13…Rc8: The rook goes to the c-file and supports c5.
14.Rc1: The rook goes to c1 against your rook on c8 – the c-file is contested.
14…b5: 14...b5 gains space on the queenside and attacks the pawn on c4.
15.Bf1: The bishop goes to f1 and covers the pawn on c4.
15…cxd4: You trade on d4 and open the c-file for your rook. Stockfish: level (+0.14).

Line 11: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5 9.Nbd2 Nbd7 10.O-O O-O 11.Qc2 Rc8 12.e4 c5 13.exd5 exd5 14.Rfe1 Re8 15.dxc5 Bxc5

up to 10…O-O as line 10

11.Qc2: The queen goes to c2 and prepares e4 – she already covers the square.
11…Rc8: The rook goes to the c-file and prepares c5.
12.e4: e4 is White's plan in this set-up: it attacks d5 and wants a big pawn centre.
12…c5: c5 attacks d4: you use the fact that the bishop on c3 and the pawn on d4 stand on the same diagonal.
13.exd5: White trades on d5 and opens the e-file for his rook.
13…exd5: You recapture with the pawn – you have the hanging pawns on c5 and d5.
14.Rfe1: The rook goes to e1 and attacks your bishop on e7.
14…Re8: The rook goes to the e-file and covers the bishop on e7.
15.dxc5: White takes on c5 and leaves you an isolated pawn on d5.
15…Bxc5: You recapture with the bishop; it stands actively on c5. Stockfish: level (+0.14).

Line 12: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5 9.Nbd2 Nbd7 10.Qc2 c5 11.dxc5 bxc5 12.cxd5 exd5 13.O-O O-O 14.Rfe1 Re8 15.Rad1 Rb8

up to 9…Nbd7 as line 11

10.Qc2: The queen goes to c2 and covers c4 and e4 – it prepares e4 and eyes h7.
10…c5: c5 attacks d4: you use the fact that the bishop on c3 and the pawn on d4 stand on the same diagonal.
11.dxc5: White takes on c5 and wants to make your pawns targets.
11…bxc5: You recapture with the b-pawn and have the hanging pawns on c5 and d5.
12.cxd5: White trades on d5 and attacks the hanging pawns.
12…exd5: You recapture with the e-pawn and hold the centre.
13.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
13…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
14.Rfe1: The rook goes to e1 and attacks your bishop on e7.
14…Re8: The rook goes to the e-file and covers the bishop on e7.
15.Rad1: The rook goes to d1 against your pawn on d5.
15…Rb8: The rook goes to the b-file and eyes b3. Stockfish: level (+0.10).

Line 13: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.O-O d5 9.Qc2 Nbd7 10.Rd1 O-O 11.Bf4 Rc8 12.Nc3 Nh5 13.Bc1 Nhf6 14.Bf4

up to 7…c6 as line 12

8.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
8…d5: d5 is the core of the set-up with c6: you put a firm pawn in the centre and keep c4 under pressure.
9.Qc2: The queen goes to c2 and covers c4 and e4 – it prepares e4 and eyes h7.
9…Nbd7: The knight goes to d7 and supports the freeing moves c5 and e5.
10.Rd1: The rook goes to d1 and supports the pawn on d4.
10…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
11.Bf4: The bishop goes to f4 and eyes c7 and b8.
11…Rc8: The rook goes to the c-file and prepares c5.
12.Nc3: The knight goes to c3 and presses on your pawn on d5.
12…Nh5: The knight attacks the bishop on f4 and wants the bishop pair.
13.Bc1: The bishop steps back to c1 and avoids the trade.
13…Nhf6: Watch out: the exact move counts here. Stockfish rates 13...Nhf6 (+0.05) clearly ahead of 13...f5 (+0.54).
14.Bf4: The bishop returns to f4 – White offers a repetition. Stockfish: level (0). (transposition)

Line 14: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.O-O d5 9.Qc2 Nbd7 10.Rd1 O-O 11.Bf4 Rc8 12.Nc3 Nh5 13.Bc1 Nhf6 14.e4 dxc4 15.Bf4 b5

up to 13…Nhf6 as line 13

14.e4: e4 is White's plan in this set-up: it attacks d5 and wants a big pawn centre.
14…dxc4: Watch out: the exact move counts here. Stockfish rates 14...dxc4 (0) clearly ahead of 14...Nxe4 (+0.62).
15.Bf4: The bishop returns to f4 and eyes c7 and b8.
15…b5: 15...b5 holds the pawn on c4 and gains space. Stockfish: level (0).

Line 15: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.O-O d5 9.Qc2 Nbd7 10.Rd1 O-O 11.a4 h6 12.Be1 Qc8 13.Qa2 Qc7 14.e3 Rfe8 15.Qc2 Qc8

up to 10…O-O as line 14

11.a4: 11.a4 gains space on the queenside and threatens a5 against b6.
11…h6: 11...h6 gives your king air and takes g5 from the bishop.
12.Be1: The bishop goes to e1 and keeps the diagonal.
12…Qc8: The queen goes to c8 and eyes a6 and c4.
13.Qa2: The queen goes to a2 and covers the pawn on c4 against your bishop on a6.
13…Qc7: The queen goes to c7 and connects the rooks.
14.e3: 14.e3 supports d4 and opens the second rank.
14…Rfe8: The rook goes to e8 and prepares the freeing move e5.
15.Qc2: The queen returns to c2 and eyes h7.
15…Qc8: The queen goes back to c8 and keeps the pressure on c4. Stockfish: level (+0.19).

Line 16: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.O-O d5 9.Qc2 Nbd7 10.a4 O-O 11.Rd1

up to 9…Nbd7 as line 15

10.a4: 10.a4 gains space on the queenside and threatens a5 against b6.
10…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
11.Rd1: The rook goes to d1 and supports the pawn on d4. Stockfish: level (+0.08). (transposition)

Line 17: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.O-O d5 9.Qc2 Nbd7 10.Bf4 Rc8 11.Nbd2 c5 12.dxc5 Bxc5 13.Qb2 O-O 14.b4 Be7 15.b5 Bb7

up to 9…Nbd7 as line 16

10.Bf4: The bishop goes to f4 and eyes c7 and b8.
10…Rc8: The rook goes to the c-file and prepares c5.
11.Nbd2: The knight goes to d2 and covers c4 and e4 – it prepares the push e4.
11…c5: c5 attacks d4: you use the fact that the bishop on c3 and the pawn on d4 stand on the same diagonal.
12.dxc5: White takes on c5 and opens his bishop's diagonal.
12…Bxc5: You recapture with the bishop; it stands actively on c5.
13.Qb2: The queen goes to b2 and attacks your knight on f6.
13…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
14.b4: 14.b4 attacks your bishop on c5 and gains space.
14…Be7: The bishop retreats to e7 and covers the kingside.
15.b5: 15.b5 attacks your bishop on a6 and gains space.
15…Bb7: The bishop retreats to b7 onto the long diagonal. Stockfish: level (0).

Line 18: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.O-O d5 9.Ne5 Nfd7 10.Nxd7 Nxd7 11.Bc3 O-O 12.Nd2

up to 8…d5 as line 17

9.Ne5: The knight jumps to e5 and opens the long diagonal for the bishop on g2 – White aims at c6 and a8.
9…Nfd7: With Nfd7 you offer a knight trade: without the knight on e5 White loses the pressure against c6.
10.Nxd7: White trades on d7 – the position gets quieter, fewer pieces remain.
10…Nxd7: You recapture with the knight; it stands well on d7 and supports c5 or e5.
11.Bc3: The bishop goes to c3 onto the long diagonal: it covers d4 and faces your kingside should you play c5.
11…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
12.Nd2: The knight goes to d2 and covers c4 – so White can prepare e4 in peace. Stockfish: level (+0.07). (transposition)

Line 19: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.O-O d5 9.Ne5 Nfd7 10.Bf4 Nxe5 11.Bxe5 O-O 12.Nd2 Nd7 13.Bf4 Bf6 14.cxd5 cxd5 15.Nf3 Be7

up to 9…Nfd7 as line 18

10.Bf4: The bishop goes to f4 and supports the knight on e5.
10…Nxe5: You trade the knight on e5 – it was White's best piece.
11.Bxe5: White recaptures with the bishop; it stands strongly on e5.
11…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
12.Nd2: The knight goes to d2 and covers c4 – so White can prepare e4 in peace.
12…Nd7: The knight goes to d7 and attacks the bishop on e5.
13.Bf4: The bishop retreats to f4 and avoids the trade.
13…Bf6: The bishop goes to f6 onto the long diagonal against d4.
14.cxd5: White trades on d5 and opens the c-file for the rooks.
14…cxd5: You recapture with the c-pawn – the pawn structure is symmetrical.
15.Nf3: The knight goes to f3 and covers d4 and e5.
15…Be7: The bishop returns to e7 – a quiet, level position. Stockfish: level (0).

Line 20: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Bg2 c6 8.O-O d5 9.Bc3 Nbd7 10.Nbd2

up to 8…d5 as line 19

9.Bc3: The bishop goes to c3 onto the long diagonal: it covers d4 and faces your kingside should you play c5.
9…Nbd7: The knight goes to d7 and supports the freeing moves c5 and e5.
10.Nbd2: The knight goes to d2 and covers c4 and e4 – it prepares the push e4. Stockfish: level (+0.08). (transposition)

Line 21: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Nc3 O-O 8.e4 d5 9.cxd5 Bxf1 10.Kxf1 exd5 11.e5 Ne4 12.Kg2 Qd7 13.Re1 Nxc3 14.Bxc3 Nc6 15.h4 Nd8

up to 6…Be7 as line 20

7.Nc3: White develops the knight first. For Stockfish the second choice (+0.09) behind 7.Bg2.
7…O-O: The king first. Stockfish chooses 7...O-O (+0.1) just ahead of 7...d5 (+0.12).
8.e4: 8.e4 builds the big centre at once – White uses the fact that your bishop on a6 is still staring at c4.
8…d5: d5 attacks the centre at once – you must not let White build e4 and d5 in peace.
9.cxd5: White trades on d5 and opens the diagonal f1–a6.
9…Bxf1: Stockfish would have chosen 9...exd5 (+0.08) here; 9...Bxf1 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
10.Kxf1: The king recaptures on f1 – White loses the right to castle but keeps the centre.
10…exd5: You recapture with the pawn and have a firm pawn on d5.
11.e5: 11.e5 gains space and drives your knight from f6.
11…Ne4: Watch out: the exact move counts here. Stockfish rates 11...Ne4 (+0.2) clearly ahead of 11...Ne8 (+0.94).
12.Kg2: The king goes to g2 – an artificial castling, it stands safely there.
12…Qd7: The queen goes to d7 and connects the rooks.
13.Re1: The rook goes to e1 and attacks your knight on e4.
13…Nxc3: You trade on c3 and take away one of White's defenders of e4 and d5.
14.Bxc3: White recaptures with the bishop; it stands on the long diagonal.
14…Nc6: The knight comes to c6 and attacks the pawn on d4.
15.h4: 15.h4 gains space on the kingside – the king on g2 stands safely.
15…Nd8: The knight goes to d8 and on to e6 – there it blockades and covers d4 and f4. Stockfish: level (+0.11).

Line 22: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Nc3 O-O 8.e4 d5 9.cxd5 Bxf1 10.Kxf1 exd5 11.e5 Ne4 12.Kg2 Qd7 13.Qe2 Nxc3 14.Bxc3 Nc6 15.Rhe1 Nd8

up to 12…Qd7 as line 21

13.Qe2: The queen goes to e2 and attacks your knight on e4.
13…Nxc3: You trade on c3 and take away one of White's defenders of e4 and d5.
14.Bxc3: White recaptures with the bishop; it stands on the long diagonal.
14…Nc6: Stockfish would have chosen 14...c5 (+0.06) here; 14...Nc6 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
15.Rhe1: The rook goes to e1 and supports the pawn on e5.
15…Nd8: The knight goes to d8 and on to e6 – there it blockades and covers d4 and f4. Stockfish: level (-0.11).

Line 23: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Nc3 O-O 8.e4 d5 9.cxd5 Bxf1 10.Kxf1 exd5 11.e5 Ne4 12.Qe2 Nxc3 13.Bxc3 Qd7 14.Kg2

up to 11…Ne4 as line 22

12.Qe2: The queen goes to e2 and attacks your knight on e4.
12…Nxc3: You trade on c3 and take away one of White's defenders of e4 and d5.
13.Bxc3: White recaptures with the bishop; it stands on the long diagonal.
13…Qd7: Stockfish would have chosen 13...c5 (+0.06) here; 13...Qd7 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
14.Kg2: The king goes to g2 – an artificial castling, it stands safely there. Stockfish: level (+0.06). (transposition)

Line 24: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Nc3 O-O 8.Bg2 c6 9.e4 d5 10.exd5 cxd5 11.Ne5 Bb7 12.O-O Nc6 13.Bf4 Na5 14.Rc1 Rc8 15.Qe2 Ba3

up to 7…O-O as line 23

8.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
8…c6: 8...c6 prepares d5 and takes b5 from the knight.
9.e4: 8.e4 builds the big centre at once – White uses the fact that your bishop on a6 is still staring at c4.
9…d5: Watch out: the exact move counts here. Stockfish rates 9...d5 (+0.21) clearly ahead of 9...d6 (+1.52).
10.exd5: White trades on d5 and opens the position for his pieces.
10…cxd5: You recapture with the c-pawn and keep the pawn on d5.
11.Ne5: The knight jumps to e5 and eyes c6.
11…Bb7: The bishop goes to b7 and covers your pawn on d5.
12.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
12…Nc6: The knight comes to c6 and attacks the knight on e5.
13.Bf4: The bishop goes to f4 and supports the knight on e5.
13…Na5: The knight goes to a5 and on to c4.
14.Rc1: The rook goes to c1 onto the open c-file.
14…Rc8: The rook goes to the c-file against the rook on c1.
15.Qe2: The queen goes to e2 and connects the rooks.
15…Ba3: The bishop attacks the rook on c1 and fights for the c-file. Stockfish: level (+0.23).

Line 25: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Nc3 O-O 8.Bg2 c6 9.e4 d5 10.Qe2 b5 11.e5 Nfd7 12.cxb5 cxb5 13.Qd1 Nc6 14.O-O Rc8 15.Ne2 Ba3

up to 9…d5 as line 24

10.Qe2: The queen goes to e2 and covers c4 and e4 against your pieces.
10…b5: 10...b5 attacks the pawn on c4 and opens the queenside.
11.e5: 11.e5 drives your knight from f6 and gains space.
11…Nfd7: The knight goes to d7 and on to b6.
12.cxb5: White takes on b5 and opens the c-file for the rook.
12…cxb5: You recapture with the c-pawn and have a passed pawn on the queenside.
13.Qd1: The queen goes back to d1 and covers the pawn on d4.
13…Nc6: The knight comes to c6 and attacks the pawn on d4.
14.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
14…Rc8: The rook goes to the open c-file and eyes c1.
15.Ne2: The knight goes to e2 and covers the pawn on d4.
15…Ba3: The bishop goes to a3 and eyes the queenside. Stockfish: level (+0.22).

Line 26: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Nc3 O-O 8.Bg2 c6 9.O-O d5 10.cxd5 cxd5 11.Ne5 Nfd7 12.Nxd7 Qxd7 13.Re1 Nc6 14.Bc1 Rac8 15.Bb2 Rc7

up to 8…c6 as line 25

9.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
9…d5: Watch out: the exact move counts here. Stockfish rates 9...d5 (+0.1) clearly ahead of 9...Bb7 (+0.92).
10.cxd5: White trades on d5 and opens the c-file for the rooks.
10…cxd5: Watch out: the exact move counts here. Stockfish rates 10...cxd5 (-0.15) clearly ahead of 10...exd5 (+0.32).
11.Ne5: The knight jumps to e5 and opens the bishop on g2.
11…Nfd7: With Nfd7 you offer a knight trade: without the knight on e5 White loses the pressure against c6.
12.Nxd7: White trades on d7 – the position gets quieter, fewer pieces remain.
12…Qxd7: You recapture with the queen; she connects the rooks.
13.Re1: The rook goes to e1 and prepares the push e4.
13…Nc6: The knight comes to c6 and attacks the pawn on d4.
14.Bc1: The bishop goes to c1 and on to b2, where it covers d4.
14…Rac8: The rook goes to the open c-file against c1.
15.Bb2: The bishop reaches b2 and covers the pawn on d4.
15…Rc7: The rook goes to c7 and wants to double the rooks – you stand slightly better. Stockfish: level (-0.19).

Line 27: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Nc3 O-O 8.Bg2 c6 9.O-O d5 10.Bf4 Nbd7 11.Qd3 c5 12.Nb5 Bxb5 13.cxb5 h6 14.a4 Rc8 15.Rfc1 Re8

up to 9…d5 as line 26

10.Bf4: The bishop goes to f4 and eyes b8 and c7.
10…Nbd7: The knight goes to d7 and supports the freeing moves c5 and e5.
11.Qd3: The queen goes to d3 and covers the pawn on c4.
11…c5: c5 attacks d4: you use the fact that the bishop on c3 and the pawn on d4 stand on the same diagonal.
12.Nb5: The knight jumps to b5 and attacks a7 and d6.
12…Bxb5: You trade on b5 and take the annoying knight.
13.cxb5: White recaptures with the pawn; it stands advanced on b5.
13…h6: 13...h6 gives your king an escape square and takes g5 from White's bishop.
14.a4: 14.a4 supports the pawn on b5 and secures it.
14…Rc8: The rook goes to the c-file against the pawn on c4.
15.Rfc1: The rook goes to c1 against your rook on c8.
15…Re8: The rook goes to e8 and connects the rooks. Stockfish: level (+0.07).

Line 28: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Nc3 O-O 8.Bg2 c6 9.O-O d5 10.Ne5 dxc4 11.Bf4 cxb3 12.axb3 Bb7 13.e4 a5 14.Qf3 b5 15.Rfd1 Nbd7

up to 9…d5 as line 27

10.Ne5: The knight jumps to e5 and opens the bishop on g2.
10…dxc4: You take the pawn on c4 and attack the pawn on b3.
11.Bf4: The bishop goes to f4 and supports the knight on e5.
11…cxb3: You trade on b3 and open the a-file for White's rook.
12.axb3: White recaptures with the a-pawn; the a-file is open.
12…Bb7: The bishop goes to b7 and covers the pawn on c6.
13.e4: 13.e4 builds the centre and closes your bishop's diagonal.
13…a5: 13...a5 gains space on the queenside and covers b4.
14.Qf3: The queen goes to f3 and eyes c6 and f7.
14…b5: 14...b5 gains space on the queenside and takes c4 from the knight.
15.Rfd1: The rook goes to d1 and supports the pawn on d4.
15…Nbd7: The knight attacks the strong knight on e5 and wants to trade it. Stockfish: level (0).

Line 29: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Nc3 O-O 8.Qc2 d5 9.cxd5 exd5 10.Bg2 c5 11.O-O Nc6 12.Be3 Re8 13.Rfd1 Ng4 14.dxc5 Nb4 15.Qd2 Nxe3

up to 7…O-O as line 28

8.Qc2: The queen goes to c2 and covers e4 against your bishop.
8…d5: d5 attacks the centre at once – you must not let White build e4 and d5 in peace.
9.cxd5: White trades on d5 and opens the e-file for your rook.
9…exd5: You recapture with the pawn and have a firm pawn on d5.
10.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
10…c5: c5 attacks d4: you use the fact that the bishop on c3 and the pawn on d4 stand on the same diagonal.
11.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
11…Nc6: The knight comes to c6 and attacks the pawn on d4.
12.Be3: The bishop goes to e3 and covers the pawn on d4.
12…Re8: The rook goes to the half-open e-file against e3.
13.Rfd1: The rook goes to d1 and supports the pawn on d4.
13…Ng4: The knight attacks the bishop on e3, which covers d4.
14.dxc5: White takes on c5 and opens the position.
14…Nb4: The knight attacks the queen on c2 and gains a tempo.
15.Qd2: The queen goes to d2 and covers the bishop on e3.
15…Nxe3: You trade on e3 and get the bishop pair. Stockfish: level (-0.06).

Line 30: 4.g3 Ba6 5.b3 Bb4 6.Bd2 Be7 7.Nc3 O-O 8.Rc1 d5 9.cxd5 Nxd5 10.Bg2 Bb7 11.Nxd5 Bxd5 12.O-O Nd7 13.Bf4 Bd6 14.Qd2 h6 15.Rfd1 Rc8

up to 7…O-O as line 29

8.Rc1: The rook goes to c1 and covers the pawn on c4.
8…d5: d5 attacks the centre at once – you must not let White build e4 and d5 in peace.
9.cxd5: White trades on d5 and opens the c-file for his rook.
9…Nxd5: You recapture with the knight and offer a trade.
10.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
10…Bb7: The bishop goes to b7 and covers the knight on d5.
11.Nxd5: White trades on d5 and simplifies the position.
11…Bxd5: You recapture with the bishop; it stands centrally on d5.
12.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
12…Nd7: The knight goes to d7 and on to f6.
13.Bf4: The bishop goes to f4 and eyes d6 and b8.
13…Bd6: The bishop goes to d6 and offers a trade.
14.Qd2: The queen goes to d2 and connects the rooks.
14…h6: 14...h6 gives your king an escape square and takes g5 from White's bishop.
15.Rfd1: The rook goes to d1 and supports the pawn on d4.
15…Rc8: The rook goes to the c-file against the rook on c1. Stockfish: level (+0.12).

Line 31: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.dxc5 Bxc5 8.O-O O-O 9.Nc3 Be7 10.Rd1 Na6 11.Bf4 Nc5 12.Qc2 Qc8 13.Rac1 Nce4 14.Nd4 Nxc3 15.Qxc3 a6 16.Qb3 Bxg2 17.Kxg2 Qb7 18.Qf3 Ra7

up to 4…Ba6 as line 30

5.Qa4: The queen guards c4 and attacks the bishop on a6 – the Nimzowitsch Attack. For Stockfish just under a tenth weaker than 5.b3 and 5.Nbd2.
5…Bb7: The bishop returns to the long diagonal – the queen on a4 is then a little offside. Stockfish chooses 5...Bb7 (+0.08) ahead of 5...Be7 (+0.14).
6.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
6…c5: You attack d4 while White's queen is out of play. Stockfish chooses 6...c5 (+0.06) clearly ahead of 6...Be7 (+0.17); its line 7.dxc5 bxc5 shows Black occupying the centre with pawns.
7.dxc5: White takes. Stockfish sees 7.dxc5 (+0.05) just ahead of 7.d5 and 7.e3 (both 0).
7…Bxc5: Recapture with the bishop – it is developed at once. Stockfish had 7...bxc5 (+0.11) ahead; 7...Bxc5 (+0.17) is the second choice. The players take with the bishop in six games out of ten; the difference is six hundredths.
8.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
8…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
9.Nc3: The knight goes to c3 and covers e4 – White wants to close the long diagonal of your bishop on b7.
9…Be7: The bishop goes to e7 and covers the kingside – it is less exposed there.
10.Rd1: The rook goes to d1 and supports the pawn on d4.
10…Na6: The knight goes to a6 and on to c5 – there it attacks the queen on a4.
11.Bf4: The bishop goes to f4 and eyes d6 and b8.
11…Nc5: The knight jumps to c5 and attacks the queen on a4 – it gains time.
12.Qc2: The queen steps aside to c2 and covers e4 – your knight drove her away with tempo.
12…Qc8: The queen goes to c8 and covers the bishop on b7 – she prepares bishop takes on g2.
13.Rac1: The rook goes to c1 and eyes c5 and c7.
13…Nce4: Stockfish would have chosen 13...Rd8 (+0.03) here; 13...Nce4 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
14.Nd4: The knight jumps to d4 and opens the bishop on g2.
14…Nxc3: You trade on c3 and take away one of White's defenders.
15.Qxc3: The queen recaptures on c3 and stands on the long diagonal.
15…a6: 15...a6 takes b5 from the knight and secures c7.
16.Qb3: The queen goes to b3 and eyes b6 and b7.
16…Bxg2: You trade the light bishops on g2 – without it White has no pressure on the long diagonal.
17.Kxg2: The king recaptures on g2; the position is quiet and level.
17…Qb7: The queen goes to b7 and threatens a check on the diagonal.
18.Qf3: The queen goes to f3 and offers a queen trade. Stockfish: level (0).
18…Ra7: Stockfish would have chosen 18...Ne4 (0) here; 18...Ra7 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.

Line 32: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.dxc5 Bxc5 8.O-O O-O 9.Nc3 Be7 10.Rd1 Na6 11.Bf4 Nc5 12.Qc2 Qc8 13.Rac1 Nce4 14.Nxe4 Bxe4 15.Qd2 Qa6

up to 13…Nce4 as line 31

14.Nxe4: White trades on e4 and simplifies the position.
14…Bxe4: Watch out: the exact move counts here. Stockfish rates 14...Bxe4 (-0.03) clearly ahead of 14...Nxe4 (+0.45).
15.Qd2: The queen goes to d2 and connects the rooks.
15…Qa6: The queen goes to a6 and attacks the pawn on a2. Stockfish: level (0).

Line 33: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.dxc5 Bxc5 8.O-O O-O 9.Nc3 Be7 10.Rd1 Na6 11.Bf4 Nc5 12.Qc2 Qc8 13.Rd4 d5 14.cxd5 Nxd5 15.Bg5 Nf6

up to 12…Qc8 as line 32

13.Rd4: The rook goes to d4 and eyes your queenside.
13…d5: 13...d5 attacks the pawn on c4 and opens the centre.
14.cxd5: White trades on d5 and opens the lines.
14…Nxd5: You recapture with the knight and attack the bishop on f4.
15.Bg5: The bishop goes to g5 and attacks your bishop on e7.
15…Nf6: The knight returns to f6 and covers the bishop on e7. Stockfish: level (0).

Line 34: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.dxc5 Bxc5 8.O-O O-O 9.Nc3 Be7 10.Rd1 Na6 11.Bf4 Nc5 12.Qc2 Qc8 13.Rd4 d5 14.cxd5 Nxd5 15.Nxd5 Bxd5

up to 14…Nxd5 as line 33

15.Nxd5: White trades on d5 and attacks your bishop on e7.
15…Bxd5: You recapture with the bishop; it stands centrally on d5. Stockfish: level (+0.12).

Line 35: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.dxc5 Bxc5 8.O-O O-O 9.Nc3 Be7 10.Rd1 Na6 11.Be3 Qc8 12.Rac1 Nc5 13.Qc2 Nce4 14.Bd4 Nxc3 15.Qxc3 d6

up to 10…Na6 as line 34

11.Be3: The bishop goes to e3 and covers c5 and d4 against your knight.
11…Qc8: The queen goes to c8 and covers the bishop on b7 – she prepares bishop takes on g2.
12.Rac1: The rook goes to c1 onto the c-file and eyes c7.
12…Nc5: The knight jumps to c5 and attacks the queen on a4 – it gains time.
13.Qc2: The queen steps aside to c2 and covers e4 – your knight drove her away with tempo.
13…Nce4: The knight jumps to e4 and offers trades – every piece traded relieves you.
14.Bd4: The bishop goes to d4 and attacks your knight on f6.
14…Nxc3: You trade on c3 and take away one of White's defenders.
15.Qxc3: The queen recaptures on c3 and stands on the long diagonal.
15…d6: 15...d6 takes e5 from the bishop and holds the centre. Stockfish: level (+0.07).

Line 36: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.dxc5 Bxc5 8.O-O O-O 9.Nc3 Be7 10.Bf4 Na6 11.Rfd1

up to 9…Be7 as line 35

10.Bf4: The bishop goes to f4 and eyes b8 and d6.
10…Na6: The knight goes to a6 and on to c5 – there it attacks the queen on a4.
11.Rfd1: The rook goes to d1 and eyes your pawn on d7. Stockfish: level (+0.19). (transposition)

Line 37: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.dxc5 Bxc5 8.O-O O-O 9.Nc3 Be7 10.Bf4 Na6 11.Rad1 Nc5 12.Qc2 Qc8 13.Nb5 Nce4 14.Nd2 Nxd2 15.Bxb7 Qxb7

up to 10…Na6 as line 36

11.Rad1: The rook goes to d1 and eyes your pawn on d7.
11…Nc5: The knight jumps to c5 and attacks the queen on a4 – it gains time.
12.Qc2: The queen steps aside to c2 and covers e4 – your knight drove her away with tempo.
12…Qc8: The queen goes to c8 and covers the bishop on b7 – she prepares bishop takes on g2.
13.Nb5: The knight jumps to b5 and eyes c7 and d6.
13…Nce4: The knight jumps to e4 and offers trades – every piece traded relieves you.
14.Nd2: The knight goes to d2 and attacks your knight on e4.
14…Nxd2: You trade on d2 and attack the rook on f1.
15.Bxb7: White trades on b7 first before recapturing the knight on d2.
15…Qxb7: You recapture with the queen – the knight on d2 is still hanging. Stockfish: level (+0.06).

Line 38: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.dxc5 Bxc5 8.O-O O-O 9.Nc3 Be7 10.Bf4 Na6 11.Rac1 Nc5 12.Qc2 Qc8 13.Nd4 Bxg2 14.Kxg2 Qb7 15.f3 Rac8

up to 10…Na6 as line 37

11.Rac1: The rook goes to c1 onto the c-file and eyes c7.
11…Nc5: The knight jumps to c5 and attacks the queen on a4 – it gains time.
12.Qc2: The queen steps aside to c2 and covers e4 – your knight drove her away with tempo.
12…Qc8: The queen goes to c8 and covers the bishop on b7 – she prepares bishop takes on g2.
13.Nd4: The knight jumps to d4 and opens the bishop on g2.
13…Bxg2: You trade the light bishops on g2 – without it White has no pressure on the long diagonal.
14.Kxg2: The king recaptures on g2; the position is quiet and level.
14…Qb7: The queen goes to b7 and threatens a check.
15.f3: 15.f3 covers e4 and protects the king from the check.
15…Rac8: The rook goes to c8 against the rook on c1 – the c-file is contested. Stockfish: level (+0.07).

Line 39: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.dxc5 Bxc5 8.Nc3 O-O 9.O-O

up to 7…Bxc5 as line 38

8.Nc3: The knight goes to c3 and covers e4 – White wants to close the long diagonal of your bishop on b7.
8…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
9.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time. Stockfish: level (+0.10). (transposition)

Line 40: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.O-O cxd4 8.Nxd4 Bxg2 9.Kxg2 Qc8 10.Rd1 Be7 11.Nc3 O-O 12.f3 a6 13.Bg5 h6 14.Bxf6 Bxf6 15.Rac1 Be7

up to 6…c5 as line 39

7.O-O: White castles and allows the trade on d4. For Stockfish about a tenth weaker than 7.dxc5.
7…cxd4: You trade off the bishop on g2. Stockfish chooses 7...cxd4 (+0.07) clearly ahead of 7...Be7 (+0.14); its line 8.Nxd4 8...Bxg2 9.Kxg2 shows the plan: the dangerous bishop on g2 disappears.
8.Nxd4: White recaptures with the knight and opens the bishop on g2.
8…Bxg2: You trade the light bishops on g2 – without it White has no pressure on the long diagonal.
9.Kxg2: The king recaptures on g2; the position is quiet and level.
9…Qc8: The queen goes to c8 and threatens a check.
10.Rd1: The rook goes to d1 and supports the pawn on d4.
10…Be7: The bishop goes to e7 and covers the kingside – it is less exposed there.
11.Nc3: The knight goes to c3 and covers e4 – White wants to close the long diagonal of your bishop on b7.
11…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
12.f3: 12.f3 covers e4 and protects the king from a check on the diagonal.
12…a6: 12...a6 takes b5 from the knight and secures d6.
13.Bg5: The bishop pins your knight on f6 and wants to trade it.
13…h6: 13...h6 asks the bishop whether it trades or retreats.
14.Bxf6: White trades on f6 and gives you the bishop pair.
14…Bxf6: You recapture with the bishop and have the bishop pair.
15.Rac1: The rook goes to c1 onto the c-file and eyes c7.
15…Be7: The bishop returns to e7 and covers d6 – the Hedgehog stands. Stockfish: level (0).

Line 41: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.O-O cxd4 8.Nxd4 Bxg2 9.Kxg2 Qc8 10.Rd1 Be7 11.Nc3 O-O 12.Bf4 a6 13.e4 Qb7 14.Qc2 h6 15.Qe2 d6

up to 11…O-O as line 40

12.Bf4: The bishop goes to f4 and eyes b8 and d6.
12…a6: 12...a6 takes b5 from the knight on c3 and secures d6.
13.e4: 13.e4 builds the centre and takes d5 from your pieces.
13…Qb7: The queen goes to b7 and presses on the long diagonal against e4.
14.Qc2: The queen goes to c2 and covers the pawn on e4.
14…h6: 14...h6 gives your king air and takes g5 from the bishop.
15.Qe2: The queen goes to e2 and covers c4 and e4 at the same time.
15…d6: 15...d6 – the Hedgehog: your pawns on the sixth rank hold everything. Stockfish: level (0).

Line 42: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.O-O cxd4 8.Nxd4 Bxg2 9.Kxg2 Qc8 10.Rd1 Be7 11.Nc3 O-O 12.Bg5 h6 13.Bxf6 Bxf6 14.Ne4 Be7 15.Rac1 Rd8

up to 11…O-O as line 41

12.Bg5: The bishop pins your knight on f6 and wants to trade it – then you lack a defender of d5 and e4.
12…h6: h6 asks the bishop on g5: if it trades on f6 you get the bishop pair; if it retreats the pin is annoying but harmless.
13.Bxf6: White trades on f6 and gives you the bishop pair – in return he has time and control of e4.
13…Bxf6: You recapture with the bishop; it stands strongly on the long diagonal against d4 and b2.
14.Ne4: The knight goes to e4 and attacks your bishop on f6 – it wants to end the bishop pair.
14…Be7: The bishop returns to e7 and avoids the trade – the bishop pair is your trump.
15.Rac1: The rook goes to c1 onto the c-file and eyes c7.
15…Rd8: The rook goes to d8 and keeps the push d5 ready. Stockfish: level (0).

Line 43: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.O-O cxd4 8.Nxd4 Bxg2 9.Kxg2 Qc8 10.Nc3 Qb7 11.f3 Be7 12.Rd1 O-O 13.Bg5 h6 14.Bxf6 Bxf6 15.Ne4 Be7

up to 9…Qc8 as line 42

10.Nc3: The knight goes to c3 and covers e4 – White wants to close the long diagonal of your bishop on b7.
10…Qb7: The queen goes to b7 and threatens a check on the long diagonal.
11.f3: 11.f3 covers e4 and protects the king from the check.
11…Be7: The bishop goes to e7 and prepares castling.
12.Rd1: The rook goes to d1 and supports the knight on d4.
12…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
13.Bg5: The bishop pins your knight on f6 and wants to trade it – then you lack a defender of d5 and e4.
13…h6: h6 asks the bishop on g5: if it trades on f6 you get the bishop pair; if it retreats the pin is annoying but harmless.
14.Bxf6: White trades on f6 and gives you the bishop pair – in return he has time and control of e4.
14…Bxf6: You recapture with the bishop; it stands strongly on the long diagonal against d4 and b2.
15.Ne4: The knight goes to e4 and attacks your bishop on f6 – it wants to end the bishop pair.
15…Be7: The bishop returns to e7 and avoids the trade – the bishop pair is your trump. Stockfish: level (+0.08).

Line 44: 4.g3 Ba6 5.Qa4 Bb7 6.Bg2 c5 7.O-O cxd4 8.Nxd4 Bxg2 9.Kxg2 Qc8 10.Bf4 Be7 11.Nc3 O-O 12.Rfd1

up to 9…Qc8 as line 43

10.Bf4: The bishop goes to f4 and eyes b8 and d6.
10…Be7: The bishop goes to e7 and prepares castling.
11.Nc3: The knight goes to c3 and covers e4 – White wants to close the long diagonal of your bishop on b7.
11…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
12.Rfd1: The rook goes to d1 and supports the knight on d4. Stockfish: level (0). (transposition)

Line 45: 4.g3 Ba6 5.Nbd2 Bb4 6.Qc2 Bb7 7.Bg2 Be4 8.Qb3 Bxd2 9.Bxd2 O-O 10.O-O d6 11.Rfd1 Nbd7 12.Rac1 Qe7 13.Qa3 a5 14.Bh3 h6 15.Nh4 c5

up to 4…Ba6 as line 44

5.Nbd2: The knight guards c4 – but stays a little passive on d2. Stockfish rates 5.Nbd2 like 5.b3 (+0.14).
5…Bb4: You pin the knight to the king. Stockfish had 5...Bb7 (+0.11) and 5...d5 (+0.13) just ahead; 5...Bb4 gives away only seven hundredths.
6.Qc2: The queen guards d2 and c4. Stockfish had 6.Qa4 (+0.18) just ahead.
6…Bb7: Back to the long diagonal – c4 is guarded, now the bishop aims at e4 and f3. Stockfish had 6...O-O (+0.19) just ahead; the gap is four hundredths.
7.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
7…Be4: With tempo against the queen – the bishop occupies e4 before White can take the square with a pawn. Stockfish chooses 7...Be4 (+0.26) ahead of 7...O-O (+0.3).
8.Qb3: The queen goes to b3 and attacks your bishop on b4.
8…Bxd2: You trade the bishop for the knight on d2 – afterwards White controls e4 less.
9.Bxd2: White recaptures with the bishop and has the bishop pair, but your bishop on e4 stands strongly.
9…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
10…d6: d6 keeps e5 under control and makes room for your knight on d7 – a set-up as in the Nimzo-Indian.
11.Rfd1: The rook goes to d1 and supports the pawn on d4.
11…Nbd7: The knight goes to d7 and supports e5 or c5.
12.Rac1: The rook goes to c1 and prepares c5 to open the queenside.
12…Qe7: The queen goes to e7 and covers the queenside.
13.Qa3: The queen goes to a3 and offers a queen trade.
13…a5: 13...a5 gains space and takes b4 from White.
14.Bh3: The bishop goes to h3 and eyes e6 – it sidesteps your bishop on e4.
14…h6: 14...h6 gives your king an escape square and takes g5 from White's bishop.
15.Nh4: The knight goes to h4 and attacks your bishop on e4.
15…c5: 15...c5 attacks d4 and opens the queenside for your pieces. Stockfish: level (+0.05).

Line 46: 4.g3 Ba6 5.Nbd2 Bb4 6.Qc2 Bb7 7.Bg2 Be4 8.Qb3 Bxd2 9.Bxd2 O-O 10.O-O d6 11.Qe3 Nbd7 12.b4 Re8 13.Rfd1 h6 14.Bc3 d5 15.c5 c6

up to 10…d6 as line 45

11.Qe3: The queen goes to e3 and attacks your bishop on e4.
11…Nbd7: The knight goes to d7 and supports e5 or c5.
12.b4: 12.b4 gains space on the queenside and prepares c5.
12…Re8: The rook goes to e8 and prepares the freeing move e5.
13.Rfd1: The rook goes to d1 and supports the pawn on d4.
13…h6: 13...h6 gives your king an escape square and takes g5 from White's bishop.
14.Bc3: The bishop goes to c3 and covers d4 from the long diagonal.
14…d5: 14...d5 attacks c4 and stops White from playing d5.
15.c5: 15.c5 gains space on the queenside and closes it.
15…c6: 15...c6 supports d5 – the position is closed and solid. Stockfish: level (+0.27).

Line 47: 4.g3 Ba6 5.Nbd2 Bb4 6.Qc2 Bb7 7.Bg2 Be4 8.Qd1 O-O 9.O-O Bxd2 10.Qxd2 d6 11.b3 Nbd7 12.Bb2 Qe7 13.Bh3 c5 14.dxc5 dxc5 15.Rfd1 Rfd8

up to 7…Be4 as line 46

8.Qd1: The queen retreats to d1 and avoids your bishop on e4.
8…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
9.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
9…Bxd2: You trade the bishop for the knight on d2 – afterwards White controls e4 less.
10.Qxd2: The queen recaptures on d2 and keeps the bishop pair.
10…d6: Stockfish would have chosen 10...a5 (+0.22) here; 10...d6 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
11.b3: 11.b3 prepares the bishop on b2 on the long diagonal.
11…Nbd7: The knight goes to d7 and supports e5 or c5.
12.Bb2: The bishop goes to b2 onto the long diagonal.
12…Qe7: Stockfish would have chosen 12...a5 (+0.39) here; 12...Qe7 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
13.Bh3: The bishop goes to h3 and eyes e6 – it sidesteps your bishop on e4.
13…c5: 13...c5 attacks d4 and opens the diagonal of the bishop on b2.
14.dxc5: White takes on c5 and opens the d-file.
14…dxc5: You recapture with the d-pawn – the d-file is open.
15.Rfd1: The rook goes to d1 onto the open d-file.
15…Rfd8: The rook goes to d8 and holds the open d-file. Stockfish sees White slightly ahead (+0.52).

Line 48: 4.g3 Ba6 5.Nbd2 Bb4 6.Qc2 Bb7 7.Bg2 Be4 8.Qd1 O-O 9.O-O Bxd2 10.Qxd2 d6 11.b3 Nbd7 12.Bb2 h6 13.Bh3 Bh7 14.d5 e5 15.Nh4 b5

up to 12.Bb2 as line 47

12…h6: 12...h6 gives your king an escape square and takes g5 from White's bishop.
13.Bh3: The bishop goes to h3 and eyes e6 – it sidesteps your bishop on e4.
13…Bh7: The bishop retreats to h7 and stays on the diagonal towards b1.
14.d5: 14.d5 gains space in the centre and closes the long diagonal.
14…e5: 14...e5 closes the centre – now each side plays on its wing.
15.Nh4: The knight goes to h4 and prepares f4.
15…b5: 15...b5 attacks c4 and opens the queenside. Stockfish: level (+0.26).

Line 49: 4.g3 Ba6 5.Nbd2 Bb4 6.Qc2 Bb7 7.Bg2 Be4 8.Qd1 O-O 9.O-O Bxd2 10.Bxd2 d6 11.Bc3 a5 12.b3 Nbd7 13.Rc1 a4 14.bxa4 Qc8 15.a5 Qa6

up to 9…Bxd2 as line 48

10.Bxd2: White recaptures with the bishop and has the bishop pair.
10…d6: Stockfish would have chosen 10...a5 (+0.17) here; 10...d6 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
11.Bc3: The bishop goes to c3 onto the long diagonal.
11…a5: 11...a5 gains space on the queenside and prepares a4.
12.b3: 12.b3 supports the pawn on c4 and stops your push a4.
12…Nbd7: The knight goes to d7 and supports e5 or c5.
13.Rc1: The rook goes to c1 and covers the pawn on c4.
13…a4: 13...a4 attacks b3 and wants to open the a-file.
14.bxa4: White takes on a4 – a pawn up, but the pawns on a2 and a4 are weak.
14…Qc8: The queen goes to c8 and eyes a6 and the pawn on a4.
15.a5: 15.a5 gives the pawn back to break up your pawns.
15…Qa6: The queen goes to a6 and attacks the pawn on c4. Stockfish: level (+0.28).

Line 50: 4.g3 Ba6 5.Nbd2 Bb4 6.Qc2 Bb7 7.Bg2 Be4 8.Qa4 Bxd2 9.Bxd2 O-O 10.O-O a5 11.Rfd1 d6 12.Rac1 Qe8 13.Qxe8 Rxe8 14.Kf1 Nc6 15.h4 h6

up to 7…Be4 as line 49

8.Qa4: The queen goes to a4 with check and attacks your bishop on b4.
8…Bxd2: You trade the bishop for the knight on d2 – afterwards White controls e4 less.
9.Bxd2: White recaptures with the bishop and has the bishop pair, but your bishop on e4 stands strongly.
9…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
10…a5: 10...a5 gains space on the queenside and secures b4.
11.Rfd1: The rook goes to d1 and supports the pawn on d4.
11…d6: d6 keeps e5 under control and makes room for your knight on d7 – a set-up as in the Nimzo-Indian.
12.Rac1: The rook goes to c1 and prepares c5.
12…Qe8: The queen offers a queen trade – without queens your bishop on e4 stands strongly.
13.Qxe8: White trades queens and goes into the endgame.
13…Rxe8: You recapture with the rook; it stands on the e-file.
14.Kf1: The king goes to f1 and on to e1 – in the endgame it belongs in the centre.
14…Nc6: The knight comes to c6 and eyes b4 and d4.
15.h4: 15.h4 gains space on the kingside and prepares h5.
15…h6: 15...h6 stops the pawn on h4 and secures g5. Stockfish sees White slightly ahead (+0.36).

Line 51: 4.g3 Ba6 5.Nbd2 Bb4 6.Qa4 c5 7.a3 Bxd2 8.Bxd2 cxd4 9.Bg2 Bb7 10.O-O Bc6 11.Qd1 Bxf3 12.Bxf3 Nc6 13.Bf4 O-O 14.Bd6 Re8 15.Bxc6 dxc6 16.Qxd4 Nd5

up to 5…Bb4 as line 50

6.Qa4: The queen attacks the bishop on a6 and guards c4. Stockfish's choice (+0.18), just ahead of 6.Qc2.
6…c5: You attack d4. Stockfish had 6...Be7 (+0.05) just ahead; 6...c5 gives away five hundredths and is the move of eight out of ten players.
7.a3: White questions the bishop. Stockfish would have played 7.dxc5 (+0.15).
7…Bxd2: Watch out: here there is only one move! 7...Bxd2 (+0.3) – Stockfish rates the escape 7...b5 at +5.57 – lost.
8.Bxd2: White recaptures with the bishop and has the bishop pair.
8…cxd4: You take on d4 – a pawn up for the moment.
9.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
9…Bb7: Watch out: the exact move counts here. Stockfish rates 9...Bb7 (+0.19) clearly ahead of 9...O-O (+0.82).
10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
10…Bc6: The bishop goes to c6 and attacks the queen on a4 – tempo.
11.Qd1: The queen goes back to d1 and covers the knight on f3.
11…Bxf3: You trade on f3 and keep the pawn on d4.
12.Bxf3: White recaptures with the bishop and attacks a8.
12…Nc6: Watch out: the exact move counts here. Stockfish rates 12...Nc6 (+0.1) clearly ahead of 12...d5 (+2.58).
13.Bf4: The bishop goes to f4 and eyes d6.
13…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
14.Bd6: The bishop attacks the rook on f8 and settles on d6.
14…Re8: Watch out: the exact move counts here. Stockfish rates 14...Re8 (0) clearly ahead of 14...e5 (+0.64).
15.Bxc6: White trades on c6 and wants to win back the pawn on d4.
15…dxc6: Watch out: the exact move counts here. Stockfish rates 15...dxc6 (+0.09) clearly ahead of 15...Rc8 (+6.98).
16.Qxd4: The queen wins back the pawn on d4 – material is level.
16…Nd5: The knight jumps to d5 and stands centrally – level. Stockfish: level (0).

Line 52: 4.g3 Ba6 5.Nbd2 Bb4 6.Qa4 c5 7.dxc5 Bxc5 8.Bg2 Bb7 9.b4 Be7 10.O-O Qc7 11.Bb2 O-O 12.Rfc1 Rc8 13.b5 d6 14.Qd1 h6 15.a4 a6

up to 6…c5 as line 51

7.dxc5: Stockfish's own choice (+0.15): White opens the position.
7…Bxc5: The bishop comes back. Stockfish chooses 7...Bxc5 (+0.13) clearly ahead of 7...bxc5 (+0.25).
8.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
8…Bb7: The bishop goes to b7 onto the long diagonal.
9.b4: 9.b4 attacks your bishop on c5 and gains space.
9…Be7: The bishop retreats to e7 and covers the kingside.
10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
10…Qc7: The queen goes to c7 and eyes the c-file and h2.
11.Bb2: The bishop goes to b2 onto the long diagonal.
11…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
12.Rfc1: The rook goes to c1 against your queen on c7.
12…Rc8: The rook goes to c8 and covers the queen.
13.b5: 13.b5 gains space and takes c6 from your knight.
13…d6: d6 keeps e5 under control and makes room for your knight on d7 – a set-up as in the Nimzo-Indian.
14.Qd1: The queen goes back to d1 and covers d4.
14…h6: 14...h6 gives your king an escape square and takes g5 from White's bishop.
15.a4: 15.a4 supports the pawn on b5 and keeps your queenside tied.
15…a6: 15...a6 attacks the pawn on b5 and opens the a-file. Stockfish: level (+0.18).

Line 53: 4.g3 Ba6 5.Nbd2 Bb4 6.Qb3 c5 7.Bg2 Nc6 8.dxc5 Bxc5 9.O-O O-O 10.a3 Bb7 11.Qc2 a5 12.b3 d5 13.cxd5 exd5 14.Bb2 Ba6 15.Rfe1 Rc8

up to 5…Bb4 as line 52

6.Qb3: The queen guards c4 from b3 – for Stockfish an inaccurate move that gives away almost a quarter of a pawn against 6.Qa4. Black is slightly better afterwards.
6…c5: The lever against d4. Stockfish chooses 6...c5 (0) clearly ahead of 6...Be7 (+0.14).
7.Bg2: White develops. Stockfish sees 7.Bg2 (0) and 7.a3 (-0.01) as equal.
7…Nc6: The knight increases the pressure on d4. Stockfish is clear: 7...Nc6 (+0.1) against 7...O-O (+0.32).
8.dxc5: White takes on c5 and wants to lure your bishop from b4.
8…Bxc5: You recapture with the bishop; it stands actively on c5 and eyes f2.
9.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
9…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
10.a3: 10.a3 prepares b4 to drive your bishop away.
10…Bb7: The bishop goes to b7 onto the long diagonal against g2.
11.Qc2: The queen goes to c2 and covers e4 against your bishop.
11…a5: 11...a5 prevents b4 and keeps your bishop on c5.
12.b3: 12.b3 prepares the bishop on b2 on the long diagonal.
12…d5: 12...d5 attacks the centre and blunts the bishop on g2.
13.cxd5: White trades on d5 and attacks the knight on c6.
13…exd5: You recapture with the pawn and hold the centre.
14.Bb2: The bishop goes to b2 and eyes your knight on f6.
14…Ba6: The bishop goes to a6 and attacks e2 – it takes e1 from the rook on f1.
15.Rfe1: The rook goes to e1 onto the e-file and covers e2 against your bishop.
15…Rc8: The rook goes to the c-file against the queen on c2 – you stand actively. Stockfish: level (0).

Line 54: 4.g3 Ba6 5.Nbd2 Bb4 6.Qb3 c5 7.Bg2 Nc6 8.O-O O-O 9.Qa4 Bb7 10.d5 Bxd2 11.Nxd2 Nd4 12.Qd1 exd5 13.Nb3 dxc4 14.Bxb7 cxb3 15.Bxa8 Qxa8

up to 7…Nc6 as line 53

8.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
8…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
9.Qa4: The queen goes to a4 and attacks your bishop on b4 and the knight on c6.
9…Bb7: The bishop goes to b7 and covers the knight on c6.
10.d5: 10.d5 attacks the knight on c6 and gains space.
10…Bxd2: You trade on d2 and take away one of White's defenders of e4.
11.Nxd2: White recaptures with the knight; it covers c4 and e4.
11…Nd4: The knight jumps to d4 – a strong square in the centre.
12.Qd1: The queen goes to d1 and covers e2 against your knight.
12…exd5: You take on d5 and open the long diagonal.
13.Nb3: The knight attacks your knight on d4.
13…dxc4: You take on c4 and attack the knight on b3.
14.Bxb7: White trades on b7 and attacks the rook on a8.
14…cxb3: You take the knight on b3 – an in-between move before you lose the rook.
15.Bxa8: White takes the rook on a8 – you have already collected the knight on b3 for it.
15…Qxa8: You recapture with the queen – material is level. Stockfish: level (0).

Line 55: 4.g3 Ba6 5.Nbd2 Bb4 6.Qb3 c5 7.a3 Bxd2 8.Bxd2 O-O 9.dxc5 bxc5 10.Rc1 Nc6 11.Bg2 d5 12.cxd5 exd5 13.Qa4 Qb6 14.b4 Rfe8 15.Be3 d4

up to 6…c5 as line 54

7.a3: White questions the bishop – for Stockfish a good tenth weaker than 7.Bg2.
7…Bxd2: A move of Stockfish: you trade on d2. 7...Bxd2 (-0.06) is clearly ahead of the retreat 7...Ba5 (+0.43).
8.Bxd2: White recaptures with the bishop and has the bishop pair.
8…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
9.dxc5: White takes on c5 and wants to give you doubled or hanging pawns.
9…bxc5: You recapture with the b-pawn and open the b-file.
10.Rc1: The rook goes to c1 against your pawn on c5.
10…Nc6: The knight comes to c6 and covers c5 and d4.
11.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
11…d5: 11...d5 builds the hanging pawns c5 and d5.
12.cxd5: White trades on d5 and attacks the knight on c6.
12…exd5: You recapture with the pawn and hold the centre.
13.Qa4: The queen goes to a4 and attacks the bishop on a6 and the knight on c6.
13…Qb6: The queen goes to b6 and covers the bishop on a6 and the knight on c6.
14.b4: 14.b4 attacks your pawn on c5 and wants to break up the hanging pawns.
14…Rfe8: The rook goes to the e-file and prepares d4.
15.Be3: The bishop goes to e3 against the pawn on c5.
15…d4: 15...d4 attacks the bishop on e3 and releases the tension. Stockfish: level (0).

Line 56: 4.g3 Ba6 5.Qb3 Nc6 6.Nbd2 Na5 7.Qa4 Bb7 8.Bg2 c5 9.dxc5 bxc5 10.O-O Be7 11.Ne5 Bxg2 12.Kxg2 O-O 13.Ndf3 h6 14.Rd1 d6 15.Bd2 Nb7

up to 4…Ba6 as line 55

5.Qb3: Timman's Line: the queen guards c4 and eyes b7. Stockfish sees it on a par with 5.b3 and 5.Nbd2 (+0.16).
5…Nc6: The knight wants to go to a5 and then attacks the queen and c4. Stockfish chooses 5...Nc6 (+0.13) ahead of 5...d5 (+0.17).
6.Nbd2: White guards c4 a second time. Stockfish's choice (+0.09) ahead of 6.Bd2 (0).
6…Na5: With tempo against the queen. Stockfish chooses 6...Na5 (+0.15) ahead of 6...d5 (+0.2).
7.Qa4: The queen attacks the bishop on a6.
7…Bb7: Back to the long diagonal. Stockfish is sure: 7...Bb7 (+0.07) against 7...c5 (+0.52).
8.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
8…c5: 8...c5 attacks d4 – the usual counter.
9.dxc5: White takes on c5 and wants to give you hanging pawns.
9…bxc5: Watch out: the exact move counts here. Stockfish rates 9...bxc5 (+0.02) clearly ahead of 9...Bxc5 (+0.51).
10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
10…Be7: The bishop goes to e7 and prepares castling.
11.Ne5: The knight jumps to e5 and opens the bishop on g2.
11…Bxg2: Stockfish would have chosen 11...Qc7 (-0.16) here; 11...Bxg2 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
12.Kxg2: The king recaptures on g2; the position is quiet and level.
12…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
13.Ndf3: The knight goes to f3 and covers e5 – it replaces the traded knight.
13…h6: 13...h6 gives your king an escape square and takes g5 from White's bishop.
14.Rd1: The rook goes to d1 against your pawn on d7.
14…d6: 14...d6 takes e5 from the knight and covers c5.
15.Bd2: The bishop attacks your knight on a5.
15…Nb7: The knight retreats to b7 and covers c5 and d6. Stockfish: level (0).

Line 57: 4.g3 Ba6 5.Qb3 Nc6 6.Nbd2 Na5 7.Qa4 Bb7 8.Bg2 c5 9.O-O Be7 10.dxc5 bxc5

up to 8…c5 as line 56

9.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
9…Be7: The bishop goes to e7 and prepares castling.
10.dxc5: White takes on c5 and wants to give you hanging pawns.
10…bxc5: You recapture with the b-pawn and open the b-file. Stockfish: level (+0.04). (transposition)

Line 58: 4.g3 Ba6 5.Qb3 Nc6 6.Nbd2 Na5 7.Qc3 c5 8.dxc5 bxc5 9.e4 Bb7 10.e5 Ne4 11.Nxe4 Bxe4 12.Bg2 Be7 13.O-O Rb8 14.Bf4 Nc6 15.Rfe1 Bxf3

up to 6…Na5 as line 57

7.Qc3: Stockfish's choice (+0.07): the queen guards c4 and eyes the long diagonal.
7…c5: The lever against d4. Stockfish chooses 7...c5 (+0.06) ahead of 7...d5 (+0.16).
8.dxc5: White takes on c5 and opens the queen's diagonal.
8…bxc5: Watch out: the exact move counts here. Stockfish rates 8...bxc5 (+0.14) clearly ahead of 8...Bb7 (+0.78).
9.e4: 9.e4 builds the centre and takes d5 from your knight.
9…Bb7: The bishop goes to b7 and attacks the pawn on e4.
10.e5: 10.e5 drives your knight away and gains space.
10…Ne4: Watch out: the exact move counts here. Stockfish rates 10...Ne4 (+0.03) clearly ahead of 10...Ng4 (+0.43).
11.Nxe4: White trades on e4 and takes your active knight.
11…Bxe4: Watch out: the exact move counts here. Stockfish rates 11...Bxe4 (+0.1) clearly ahead of 11...Qb6 (+6.53).
12.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
12…Be7: The bishop goes to e7 and prepares castling.
13.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
13…Rb8: The rook goes to the half-open b-file against b2.
14.Bf4: The bishop goes to f4 and supports the pawn on e5.
14…Nc6: The knight comes to c6 and eyes d4 and e5.
15.Rfe1: The rook goes to e1 and attacks your bishop on e4 – you have to decide.
15…Bxf3: You trade on f3 and simplify – level. Stockfish: level (+0.03).

Line 59: 4.g3 Ba6 5.Qb3 Nc6 6.Nbd2 Na5 7.Qc2 c5 8.e4 cxd4 9.e5 Ng4 10.h3 Nh6 11.a3 Bb7 12.Bg2 Rc8 13.O-O Nf5 14.Qd3 d6 15.b4 Nc6

up to 6…Na5 as line 58

7.Qc2: The queen retreats to c2 – for Stockfish the third choice (-0.01).
7…c5: Watch out: only 7...c5 keeps the balance. Stockfish rates 7...c5 (+0.01) far ahead of 7...Be7 (+0.67).
8.e4: 8.e4 builds the centre, but the pawn on d4 hangs.
8…cxd4: Watch out: the exact move counts here. Stockfish rates 8...cxd4 (-0.39) clearly ahead of 8...d6 (+1.22).
9.e5: 9.e5 drives your knight away and gains space.
9…Ng4: A move of Stockfish. Watch out: the exact move counts here. Stockfish rates 9...Ng4 (-0.44) clearly ahead of 9...Ng8 (0).
10.h3: 10.h3 attacks the knight on g4 and drives it away.
10…Nh6: The knight goes to h6 and on to f5.
11.a3: 11.a3 prevents bishop to b4 and prepares b4.
11…Bb7: The bishop goes to b7 and attacks the knight on f3.
12.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
12…Rc8: The rook goes to the c-file against the queen on c2.
13.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
13…Nf5: The knight reaches f5 – a strong square from which it attacks d4.
14.Qd3: The queen attacks the knight on f5 and wants the pawn on d4 back.
14…d6: 14...d6 attacks the pawn on e5 and opens the position.
15.b4: 15.b4 attacks your knight on a5 and gains space on the queenside.
15…Nc6: The knight returns to c6 – you stand slightly better. Stockfish: level (-0.13).

Line 60: 4.g3 Ba6 5.Qb3 Nc6 6.Bd2 Bb7 7.Bc3 Ne4 8.a3 Nxc3 9.Qxc3 Be7 10.Bg2 Bf6 11.O-O Nxd4 12.Nxd4 Bxg2 13.Kxg2 c5 14.Nxe6 dxe6 15.Qb3 Qc7

up to 5…Nc6 as line 59

6.Bd2: White covers the square b4. Stockfish sees 6.Bd2 (0) as the second choice behind 6.Nbd2.
6…Bb7: The bishop to the long diagonal. Stockfish sees 6...Bb7 and 6...Rb8 as equal (0).
7.Bc3: The bishop opposes yours on the long diagonal.
7…Ne4: The knight attacks the bishop on c3. Stockfish chooses 7...Ne4 (-0.07) ahead of 7...a5 (+0.1) – Black is slightly better.
8.a3: 8.a3 prevents bishop to b4 and keeps your knight on e4.
8…Nxc3: You trade the bishop on c3 and take the long diagonal from White.
9.Qxc3: The queen recaptures and stands on the long diagonal.
9…Be7: The bishop goes to e7 and prepares castling.
10.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
10…Bf6: The bishop goes to f6 and attacks the pawn on d4.
11.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
11…Nxd4: You take the pawn on d4 – a small tactical trick.
12.Nxd4: White recaptures; now you trade bishops.
12…Bxg2: You trade the light bishops on g2 – without it White has no pressure on the long diagonal.
13.Kxg2: The king recaptures on g2; the position is quiet and level.
13…c5: 13...c5 attacks the knight on d4 and wins the piece back.
14.Nxe6: The knight takes on e6 and gives itself for two pawns.
14…dxe6: You recapture on e6 – material is level and the position quiet.
15.Qb3: The queen goes to b3 and eyes e6.
15…Qc7: The queen goes to c7 and covers everything – level. Stockfish: level (0).

Line 61: 4.g3 Ba6 5.Qb3 Nc6 6.Bd2 Bb7 7.d5 Ne7 8.dxe6 fxe6 9.Bg2 Nf5 10.O-O Bc5 11.Qd3 Be4 12.Qb3 O-O 13.Bc3 Bc6 14.Nbd2 Ne4 15.Nxe4 Bxe4

up to 6…Bb7 as line 60

7.d5: White chases the knight. Stockfish sees 7.d5 (0) as the best choice.
7…Ne7: Stockfish chooses 7...Ne7 (0) ahead of 7...exd5 (+0.12).
8.dxe6: White takes on e6 and opens the f-file for you.
8…fxe6: You recapture with the f-pawn and open the f-file.
9.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
9…Nf5: The knight goes to f5 and eyes d4 and e3.
10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
10…Bc5: The bishop goes to c5 and eyes f2 – together with the rook on f8 pressure looms.
11.Qd3: The queen attacks your knight on f5 and prevents knight to e3.
11…Be4: The bishop attacks the queen on d3 and gains a tempo.
12.Qb3: The queen returns to b3 and eyes e6.
12…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
13.Bc3: The bishop goes to c3 onto the long diagonal.
13…Bc6: The bishop goes to c6 and keeps the diagonal against g2.
14.Nbd2: The knight goes to d2 and attacks your bishop on e4.
14…Ne4: The knight jumps to e4 and offers a trade.
15.Nxe4: White trades on e4 and simplifies before your knight becomes too strong.
15…Bxe4: You recapture with the bishop – level. Stockfish: level (+0.10).

Chapter 2: 4.a3

Line 62: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.Qc2 Nxc3 8.bxc3 Be7 9.e4 O-O 10.Bd3 c5 11.O-O Qc8 12.Qe2 Ba6 13.Rd1 Bxd3 14.Rxd3 Nd7 15.e5 cxd4 16.cxd4 Qc4 17.Bg5 f6

4.a3: The Petrosian Variation: White takes the square b4 from the bishop before playing Nc3. Stockfish sees 4.a3 (+0.17) level with 4.g3; the players choose it in almost three games out of ten.
4…Bb7: The bishop goes to the long diagonal and controls e4. Stockfish chooses 4...Bb7 (+0.14) ahead of 4...d5 (+0.17).
5.Nc3: The Kasparov–Petrosian Variation: now the knight comes without Bb4 being able to pin it.
5…d5: The main line: you put a pawn in the centre and hold e4. Stockfish chooses 5...d5 (+0.14) ahead of 5...Ne4 (+0.21).
6.cxd5: White trades in the centre. Stockfish sees 6.Qc2 (+0.17), 6.cxd5 (+0.15) and 6.Bf4 (+0.13) as almost equal.
6…Nxd5: Recapture with the knight – the Modern Variation. The knight stands centrally and can trade on c3. Stockfish chooses 6...Nxd5 (+0.16) ahead of 6...exd5 (+0.21).
7.Qc2: The queen prepares e4. Stockfish would have played 7.e3 (+0.16).
7…Nxc3: You trade before e4 comes with tempo. Stockfish chooses 7...Nxc3 (+0.08) ahead of 7...Be7 (+0.15); after 8.bxc3 White has a strong centre but a weak pawn on c3.
8.bxc3: White recaptures with the pawn: the pawn on c3 supports d4, and White can now play e4.
8…Be7: The bishop goes to e7 and prepares castling.
9.e4: e4 builds the big pawn centre d4–e4 – your task now is to attack it with c5 and piece pressure.
9…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
10.Bd3: The bishop goes to d3 and eyes h7 – it covers e4 and prepares castling.
10…c5: c5 attacks the centre: you want to put d4 under pressure before White gains space with d5.
11.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
11…Qc8: Stockfish would have chosen 11...Qc7 (+0.15) here; 11...Qc8 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
12.Qe2: The queen goes to e2 and covers the pawn on e4.
12…Ba6: The bishop goes to a6 and offers a trade against the bishop on d3 – without it White's attack is weaker.
13.Rd1: The rook goes to d1 behind the pawn on d4 and supports it for a later advance.
13…Bxd3: You trade on d3 – without this bishop White has less of an attack on your king.
14.Rxd3: The rook recaptures on d3 and stands actively on the third rank.
14…Nd7: The knight goes to d7 and on to b6 or f8.
15.e5: 15.e5 gains space and takes f6 from your knight.
15…cxd4: You trade on d4 and open the c-file for your rook.
16.cxd4: White recaptures with the c-pawn and has a big centre d4–e5.
16…Qc4: Stockfish would have chosen 16...b5 (0) here; 16...Qc4 gives away about three tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
17.Bg5: The bishop attacks your bishop on e7 and wants to trade.
17…f6: 17...f6 attacks the bishop and the pawn on e5. Stockfish: level (+0.28).

Line 63: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.Qc2 Nxc3 8.bxc3 Be7 9.e4 O-O 10.Bd3 c5 11.O-O Qc8 12.Qe2 Ba6 13.Bf4 Bxd3 14.Qxd3 Qa6 15.Qxa6 Nxa6

up to 12…Ba6 as line 62

13.Bf4: The bishop goes to f4 and eyes b8 and d6.
13…Bxd3: You trade on d3 and take White's attacking bishop.
14.Qxd3: The queen recaptures on d3 and eyes h7.
14…Qa6: The queen offers a queen trade – in the endgame the big centre bothers you less.
15.Qxa6: White trades queens and goes into the endgame.
15…Nxa6: You recapture with the knight – a quiet endgame. Stockfish: level (+0.12).

Line 64: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.Qc2 Nxc3 8.bxc3 Be7 9.e4 O-O 10.Bd3 c5 11.O-O Qc8 12.Qa2 Rd8 13.Bf4 Nc6 14.d5 Na5 15.c4 b5

up to 11…Qc8 as line 63

12.Qa2: The queen goes to a2 and eyes f7.
12…Rd8: The rook goes to d8 and increases the pressure on d4.
13.Bf4: The bishop goes to f4 and eyes b8.
13…Nc6: The knight comes to c6 and attacks the pawn on d4.
14.d5: 14.d5 attacks the knight on c6 and gains space.
14…Na5: The knight goes to a5 and on to c4 – there it stands in front of the weak pawn on c3.
15.c4: 15.c4 supports the passed pawn on d5 – White holds it with pawns.
15…b5: 15...b5 attacks c4 and wants to undermine the passed pawn on d5. Stockfish: level (+0.02).

Line 65: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.Qc2 Nxc3 8.bxc3 Be7 9.e3 Nd7 10.Bd3 Bxf3 11.gxf3 c5 12.f4 g6 13.h4 Nf6 14.Bb2 cxd4 15.Qa4 Kf8

up to 8…Be7 as line 64

9.e3: 9.e3 supports d4 and opens the bishop on f1 – White plays quietly.
9…Nd7: The knight goes to d7 and on to f6.
10.Bd3: The bishop goes to d3 and eyes h7.
10…Bxf3: You trade on f3 and break up White's pawn structure.
11.gxf3: White recaptures with the g-pawn and gets doubled pawns.
11…c5: 11...c5 attacks d4 – with the bishop on b7 and the knight on d7 you have central pressure.
12.f4: 12.f4 gains space and covers e5 – the doubled pawns become a battering ram.
12…g6: 12...g6 takes f5 from the bishop and covers h5.
13.h4: 13.h4 attacks on the kingside and threatens h5.
13…Nf6: The knight returns to f6 and covers h5.
14.Bb2: The bishop goes to b2 onto the long diagonal.
14…cxd4: You take on d4 and open the position.
15.Qa4: The queen gives check on a4 and prevents your castling.
15…Kf8: The king goes to f8 – it stands safely enough there. Stockfish: level (0).

Line 66: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.Qc2 Nxc3 8.Qxc3 Nd7 9.Bg5 Be7 10.Bxe7 Kxe7 11.g3 Nf6 12.Bg2 Qd6 13.O-O Rhc8 14.b4 a5 15.Ne5 Bxg2

up to 7…Nxc3 as line 65

8.Qxc3: The queen recaptures on c3 and stands on the long diagonal.
8…Nd7: Stockfish would have chosen 8...h6 (0) here; 8...Nd7 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
9.Bg5: The bishop attacks your queen on d8 and forces you to interpose the bishop.
9…Be7: The bishop interposes and offers a trade.
10.Bxe7: White trades on e7 – your king recaptures and stands well in the endgame.
10…Kxe7: Watch out: the exact move counts here. Stockfish rates 10...Kxe7 (+0.13) clearly ahead of 10...Qxe7 (+0.73).
11.g3: 11.g3 prepares the bishop on g2 – it is to press on the long diagonal against your pawn on d5.
11…Nf6: The knight returns to f6 and covers d5.
12.Bg2: The bishop goes to g2 onto the long diagonal – the Catalan set-up against your queenside.
12…Qd6: The queen goes to d6 and connects the rooks.
13.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
13…Rhc8: The rook goes to c8 against the queen on c3.
14.b4: 14.b4 gains space on the queenside and prepares b5 or c5.
14…a5: 14...a5 attacks the pawn on b4 before White plays b5.
15.Ne5: The knight jumps to e5 and opens the bishop on g2.
15…Bxg2: You trade on g2 and end the pressure on the diagonal. Stockfish: level (0).

Line 67: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.Qc2 Nxc3 8.Qxc3 Nd7 9.Bg5 Be7 10.Bxe7 Kxe7 11.e3 Nf6 12.Rc1 Rc8 13.b4 Bxf3 14.gxf3 c6 15.Bg2 g5

up to 10…Kxe7 as line 66

11.e3: 11.e3 supports d4 and opens the bishop on f1 – White plays quietly.
11…Nf6: Stockfish would have chosen 11...c5 (0) here; 11...Nf6 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
12.Rc1: The rook goes to c1 onto the c-file – it will open after c5 or cxd5.
12…Rc8: The rook goes to c8 against the rook on c1.
13.b4: 13.b4 gains space on the queenside and prepares b5 or c5.
13…Bxf3: You trade on f3 and give White doubled pawns.
14.gxf3: White recaptures with the g-pawn and gets doubled pawns on the f-file.
14…c6: 14...c6 supports d5 against the bishop on g2.
15.Bg2: The bishop goes to g2 and presses on your pawn on d5.
15…g5: 15...g5 gains space on the kingside and stops the f3-pawn advancing. Stockfish: level (+0.17).

Line 68: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.e3 Be7 8.Bb5 c6 9.Bd3 O-O 10.e4 Nxc3 11.bxc3 c5 12.O-O cxd4 13.cxd4 Nc6 14.Be3 Rc8 15.Qe2 Na5 16.Rfe1 h6

up to 6…Nxd5 as line 67

7.e3: Stockfish's first choice (+0.16): White sets up calmly; the bishop on f1 comes to d3 or b5.
7…Be7: You develop. Stockfish sees 7...Nxc3 (+0.19) and 7...Be7 (+0.21) as equal.
8.Bb5: The bishop gives check on b5 and disturbs your development.
8…c6: 8...c6 blocks the check and supports d5.
9.Bd3: The bishop retreats to d3 – c6 has slightly shut in your bishop on b7.
9…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
10.e4: 10.e4 attacks your knight on d5 and builds the big centre.
10…Nxc3: Watch out: the exact move counts here. Stockfish rates 10...Nxc3 (+0.18) clearly ahead of 10...Nc7 (+0.75).
11.bxc3: White recaptures with the pawn: the pawn on c3 supports d4, and White can now play e4.
11…c5: c5 attacks the centre: you want to put d4 under pressure before White gains space with d5.
12.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
12…cxd4: You trade on d4 and open the c-file for your rook.
13.cxd4: White recaptures with the pawn and has a big centre – but also a pawn you can attack.
13…Nc6: The knight comes to c6 and attacks the pawn on d4.
14.Be3: The bishop goes to e3 and covers d4 against your knight.
14…Rc8: The rook goes to the c-file – after the trade on d4 it belongs to you.
15.Qe2: The queen goes to e2, covers e4 and connects the rooks – White prepares e4.
15…Na5: The knight goes to a5 and on to c4 – there it stands in front of the weak pawn on c3.
16.Rfe1: The rook goes to e1 and supports the push e5.
16…h6: 16...h6 gives your king an escape square and takes g5 from White's bishop. Stockfish: level (+0.04).

Line 69: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.e3 Be7 8.Bb5 c6 9.Bd3 O-O 10.e4 Nxc3 11.bxc3 c5 12.O-O cxd4 13.cxd4 Nc6 14.Be3 Rc8 15.Qe2 Na5 16.Rfd1 Rc3

up to 15…Na5 as line 68

16.Rfd1: The rook goes to d1 and supports d4 – White holds the centre with all his pieces.
16…Rc3: The rook invades c3 and attacks the bishop on d3. Stockfish: level (+0.15).

Line 70: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.e3 Be7 8.Bb5 c6 9.Bd3 O-O 10.e4 Nxc3 11.bxc3 c5 12.O-O cxd4 13.cxd4 Nc6 14.Bb2 Bf6 15.Bc2 Rc8

up to 13…Nc6 as line 69

14.Bb2: The bishop goes to b2 and covers d4 – on the long diagonal it faces your king.
14…Bf6: The bishop goes to f6 and attacks the pawn on d4.
15.Bc2: The bishop goes to c2 and eyes h7.
15…Rc8: The rook goes to the c-file – after the trade on d4 it belongs to you. Stockfish: level (+0.17).

Line 71: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.e3 Be7 8.Bb5 c6 9.Bd3 O-O 10.Qc2 h6 11.e4 Nxc3 12.bxc3 c5 13.O-O Qc8 14.Qe2 Ba6 15.Rd1 Bxd3 16.Rxd3 Nd7

up to 9…O-O as line 70

10.Qc2: The queen goes to c2 and eyes h7.
10…h6: 10...h6 gives your king an escape square and takes g5 from White's bishop.
11.e4: 11.e4 attacks your knight on d5 and builds the big centre.
11…Nxc3: Watch out: the exact move counts here. Stockfish rates 11...Nxc3 (+0.1) clearly ahead of 11...Nc7 (+1.01).
12.bxc3: White recaptures with the pawn: the pawn on c3 supports d4, and White can now play e4.
12…c5: c5 attacks the centre: you want to put d4 under pressure before White gains space with d5.
13.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
13…Qc8: Stockfish would have chosen 13...Qc7 (+0.05) here; 13...Qc8 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
14.Qe2: The queen goes to e2, covers e4 and connects the rooks – White prepares e4.
14…Ba6: Stockfish would have chosen 14...Qc7 (+0.14) here; 14...Ba6 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
15.Rd1: The rook goes to d1 behind the pawn on d4 and supports it for a later advance.
15…Bxd3: You trade on d3 and take White's attacking bishop.
16.Rxd3: The rook recaptures on d3 and stands actively on the third rank.
16…Nd7: The knight goes to d7 and on to f6. Stockfish sees White slightly ahead (+0.37).

Line 72: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.e3 Be7 8.Bb5 c6 9.Bd3 O-O 10.Qc2 h6 11.O-O c5 12.e4 Nxc3 13.bxc3

up to 10…h6 as line 71

11.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
11…c5: c5 attacks the centre: you want to put d4 under pressure before White gains space with d5.
12.e4: 12.e4 attacks your knight on d5 and builds the big centre.
12…Nxc3: You trade on c3 and give White doubled pawns – in return he builds a big centre with e4.
13.bxc3: White recaptures with the pawn: the pawn on c3 supports d4, and White can now play e4. Stockfish: level (+0.05). (transposition)

Line 73: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.e3 Be7 8.Bb5 c6 9.Bd3 O-O 10.O-O c5 11.Nxd5 Qxd5 12.dxc5 Rd8 13.Be2 Qxc5 14.Bd2 Bf6 15.Rc1 Qe7

up to 9…O-O as line 72

10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
10…c5: c5 attacks the centre: you want to put d4 under pressure before White gains space with d5.
11.Nxd5: White trades on d5 and simplifies – with fewer pieces his space advantage counts less.
11…Qxd5: You recapture with the queen; she stands centrally.
12.dxc5: White takes on c5 and wins a pawn for the moment.
12…Rd8: The rook goes to d8 and attacks the bishop on d3.
13.Be2: The bishop retreats to e2 and no longer covers the pawn on c4.
13…Qxc5: The queen wins back the pawn on c5 – material is level.
14.Bd2: The bishop goes to d2 and connects the rooks.
14…Bf6: The bishop goes to f6 and eyes b2.
15.Rc1: The rook attacks your queen on c5 and gains a tempo.
15…Qe7: The queen goes to e7 and stands safely behind your pawns. Stockfish: level (0).

Line 74: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.e3 Be7 8.Bb5 c6 9.Bd3 O-O 10.O-O c5 11.e4 Nxc3 12.bxc3

up to 10…c5 as line 73

11.e4: 11.e4 attacks your knight on d5 and builds the big centre.
11…Nxc3: You trade on c3 and give White doubled pawns – in return he builds a big centre with e4.
12.bxc3: White recaptures with the pawn: the pawn on c3 supports d4, and White can now play e4. Stockfish: level (+0.16). (transposition)

Line 75: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.e3 Be7 8.Bb5 c6 9.Bd3 O-O 10.Bd2 c5 11.O-O cxd4 12.Nxd4 Nf6 13.Qe2 a6 14.Rfd1 Nbd7 15.Be1 Qb8

up to 9…O-O as line 74

10.Bd2: The bishop goes to d2 and connects the pieces.
10…c5: c5 attacks the centre: you want to put d4 under pressure before White gains space with d5.
11.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
11…cxd4: You trade on d4 and open the c-file.
12.Nxd4: White recaptures with the knight; it stands centrally.
12…Nf6: The knight returns to f6 and covers the kingside.
13.Qe2: The queen goes to e2 and connects the rooks.
13…a6: 13...a6 takes b5 from the knight on d4.
14.Rfd1: The rook goes to d1 against your pawn on d7.
14…Nbd7: The knight goes to d7 and covers c5 and e5.
15.Be1: The bishop goes to e1 and makes room for the rook.
15…Qb8: The queen goes to b8 – the Hedgehog: she covers everything and waits for b5 or d5. Stockfish: level (+0.01).

Line 76: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.e3 Be7 8.Bd3 Nxc3 9.bxc3 c5 10.O-O Nc6 11.Qe2 O-O 12.Bb2 Rc8 13.Rad1 Qc7 14.c4 Na5 15.d5 exd5

up to 7…Be7 as line 75

8.Bd3: The bishop goes to d3 and eyes h7 – it covers e4 and prepares castling.
8…Nxc3: You trade on c3 and give White doubled pawns – in return he builds a big centre with e4.
9.bxc3: White recaptures with the pawn: the pawn on c3 supports d4, and White can now play e4.
9…c5: c5 attacks the centre: you want to put d4 under pressure before White gains space with d5.
10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
10…Nc6: The knight comes to c6 and attacks the pawn on d4.
11.Qe2: The queen goes to e2, covers e4 and connects the rooks – White prepares e4.
11…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
12.Bb2: The bishop goes to b2 and covers d4 – on the long diagonal it faces your king.
12…Rc8: Stockfish would have chosen 12...Na5 (+0.13) here; 12...Rc8 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
13.Rad1: The rook goes to d1 and supports d4 – White holds the centre with all his pieces.
13…Qc7: The queen goes to c7 and eyes h2.
14.c4: 14.c4 opens the diagonal of the bishop on b2.
14…Na5: The knight goes to a5 and on to c4 – there it stands in front of the weak pawn on c3.
15.d5: 15.d5 opens the centre for the bishop on b2.
15…exd5: You take on d5 and open the lines. Stockfish: level (+0.27).

Line 77: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.e3 Be7 8.Bd3 Nxc3 9.bxc3 c5 10.O-O Nc6 11.Qe2 O-O 12.Rd1 Na5 13.dxc5 Qc7 14.cxb6 axb6 15.Nd4 Rfd8

up to 11…O-O as line 76

12.Rd1: The rook goes to d1 and supports d4 – White holds the centre with all his pieces.
12…Na5: The knight goes to a5 and on to c4 – there it stands in front of the weak pawn on c3.
13.dxc5: White takes on c5 and opens the d-file.
13…Qc7: The queen attacks the pawn on c5 and wants to win it back.
14.cxb6: White takes on b6 and attacks your queen.
14…axb6: You recapture with the a-pawn and open the a-file.
15.Nd4: The knight jumps to d4 and eyes b5.
15…Rfd8: The rook goes to d8 against the knight on d4. Stockfish: level (+0.12).

Line 78: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.e3 Be7 8.Bd3 Nxc3 9.bxc3 c5 10.O-O Nc6 11.Bb2 Rc8 12.Qe2 O-O

up to 10…Nc6 as line 77

11.Bb2: The bishop goes to b2 and covers d4 – on the long diagonal it faces your king.
11…Rc8: Stockfish would have chosen 11...Qc7 (+0.12) here; 11...Rc8 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
12.Qe2: The queen goes to e2, covers e4 and connects the rooks – White prepares e4.
12…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open. Stockfish: level (+0.27). (transposition)

Line 79: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.e3 Be7 8.Bd3 Nxc3 9.bxc3 c5 10.O-O Nc6 11.e4 cxd4 12.cxd4 O-O

up to 10…Nc6 as line 78

11.e4: e4 builds the big pawn centre d4–e4 – your task now is to attack it with c5 and piece pressure.
11…cxd4: You trade on d4 and open the c-file for your rook.
12.cxd4: White recaptures with the pawn and has a big centre – but also a pawn you can attack.
12…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open. Stockfish: level (+0.17). (transposition)

Line 80: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.e3 Be7 8.Bd3 Nxc3 9.bxc3 c5 10.e4 Nc6 11.h4 O-O 12.Be3 Rc8 13.Qe2 h6 14.e5 f5 15.exf6 Bxf6

up to 9…c5 as line 79

10.e4: e4 builds the big pawn centre d4–e4 – your task now is to attack it with c5 and piece pressure.
10…Nc6: Stockfish would have chosen 10...Qc7 (+0.09) here; 10...Nc6 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
11.h4: 11.h4 gains space on the kingside and prepares an attack.
11…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
12.Be3: The bishop goes to e3 and covers d4 against your knight.
12…Rc8: The rook goes to the c-file – after the trade on d4 it belongs to you.
13.Qe2: The queen goes to e2, covers e4 and connects the rooks – White prepares e4.
13…h6: 13...h6 gives your king an escape square and takes g5 from White's bishop.
14.e5: 14.e5 gains space and takes f6 from your knight.
14…f5: 14...f5 stops White's attack on the kingside.
15.exf6: White takes en passant and opens the position.
15…Bxf6: You recapture with the bishop; it stands strongly on f6. Stockfish: level (0).

Line 81: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.Bd2 Nd7 8.Qc2 c5 9.e4 Nxc3 10.Bxc3 cxd4 11.Nxd4 a6 12.g3 Rc8 13.Bg2 Be7 14.O-O O-O 15.Qe2 Rc7

up to 6…Nxd5 as line 80

7.Bd2: The bishop guards c3 – for Stockfish a sixth of a pawn weaker than 7.e3.
7…Nd7: Stockfish chooses 7...Nd7 (0) ahead of 7...Be7 (+0.07): the knight supports c5.
8.Qc2: The queen goes to c2 and prepares e4.
8…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
9.e4: 9.e4 attacks your knight on d5 and builds the centre.
9…Nxc3: You trade on c3 – White's bishop has to recapture.
10.Bxc3: White recaptures with the bishop; it stands on the long diagonal.
10…cxd4: You trade on d4 and open the c-file against the bishop on c3.
11.Nxd4: White recaptures with the knight; it stands centrally on d4.
11…a6: 11...a6 takes b5 from the knight on d4.
12.g3: 12.g3 prepares the bishop on g2 against your queenside.
12…Rc8: The rook goes to the c-file against the bishop on c3.
13.Bg2: The bishop goes to g2 onto the long diagonal.
13…Be7: The bishop goes to e7 and prepares castling.
14.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
14…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
15.Qe2: The queen goes to e2, covers e4 and connects the rooks – White prepares e4.
15…Rc7: The rook goes to c7 and wants to double the rooks on the c-file. Stockfish: level (-0.08).

Line 82: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.Bd2 Nd7 8.Qc2 c5 9.Nxd5 exd5 10.dxc5 bxc5 11.e4 dxe4 12.Ng5 Qb6 13.Nxe4 Be7 14.O-O-O O-O 15.Ng5 g6

up to 8…c5 as line 81

9.Nxd5: White trades on d5 and simplifies – with fewer pieces his space advantage counts less.
9…exd5: You recapture with the pawn: you have a firm pawn on d5, and your bishop on b7 stands a little quiet behind it.
10.dxc5: White takes on c5 and wants to give you hanging pawns.
10…bxc5: You recapture with the b-pawn and have the hanging pawns c5 and d5 – strong as long as they stay together.
11.e4: 11.e4 attacks the hanging pawns at once.
11…dxe4: You take on e4 and open the diagonal of your bishop on b7.
12.Ng5: The knight goes to g5 and attacks the pawn on e4.
12…Qb6: The queen goes to b6 and eyes b2 and f2.
13.Nxe4: The knight wins back the pawn on e4.
13…Be7: The bishop goes to e7 and prepares castling.
14.O-O-O: White castles long – the kings stand on opposite sides.
14…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
15.Ng5: The knight goes to g5 and eyes h7.
15…g6: 15...g6 covers h7 and holds the position together. Stockfish: level (+0.02).

Line 83: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.Bd2 Nd7 8.Nxd5 exd5 9.g3 Bd6 10.Bg5 Be7 11.Bxe7 Qxe7 12.Rc1 Nf6 13.Bg2 O-O 14.b4 a5 15.Qb3 Rfc8

up to 7…Nd7 as line 82

8.Nxd5: White trades on d5 and simplifies – with fewer pieces his space advantage counts less.
8…exd5: You recapture with the pawn: you have a firm pawn on d5, and your bishop on b7 stands a little quiet behind it.
9.g3: 9.g3 prepares the bishop on g2 – it is to press on the long diagonal against your pawn on d5.
9…Bd6: The bishop goes to d6 and eyes g3.
10.Bg5: The bishop attacks your queen on d8 and offers a trade.
10…Be7: The bishop interposes and offers a trade.
11.Bxe7: White trades the dark bishops – your bishop on e7 was a good defender, but you lose nothing.
11…Qxe7: Watch out: the exact move counts here. Stockfish rates 11...Qxe7 (+0.12) clearly ahead of 11...Kxe7 (+0.92).
12.Rc1: The rook goes to c1 onto the c-file, which will open after your c5.
12…Nf6: The knight returns to f6 and covers d5.
13.Bg2: The bishop goes to g2 and presses on d5 – your pawn now needs protection.
13…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
14.b4: 14.b4 starts the minority attack against your pawns.
14…a5: 14...a5 attacks b4 before White plays b5.
15.Qb3: The queen goes to b3 and attacks d5 and b7 – an annoying double attack.
15…Rfc8: The rook goes to c8 onto the c-file and sets itself against White's rook. Stockfish: level (+0.08).

Line 84: 4.a3 Bb7 5.Nc3 d5 6.cxd5 Nxd5 7.Bd2 Nd7 8.Nxd5 exd5 9.b4 Nf6 10.e3 Bd6 11.Bd3 Ne4 12.Qc2 O-O 13.O-O Qe7 14.Rfc1 Nxd2 15.Nxd2 g6

up to 8…exd5 as line 83

9.b4: 9.b4 gains space on the queenside and prepares b5 or c5.
9…Nf6: The knight returns to f6 and covers d5 and e4.
10.e3: 10.e3 supports d4 and opens the bishop on f1 – White plays quietly.
10…Bd6: The bishop goes to d6 and eyes b4 and h2.
11.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling.
11…Ne4: The knight jumps to e4 and attacks the bishop on d2.
12.Qc2: The queen goes to c2 and attacks your knight on e4.
12…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
13.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
13…Qe7: The queen goes to e7 and attacks the pawn on b4.
14.Rfc1: The rook goes to c1 onto the c-file – it will open after c5 or cxd5.
14…Nxd2: You trade on d2 and get the bishop pair.
15.Nxd2: The knight recaptures on d2 – you have traded off the bishop pair.
15…g6: 15...g6 gives your king air – you stand comfortably. Stockfish: level (-0.06).

Line 85: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.Qa4 c6 8.Bxf6 Bxf6 9.cxd5 exd5 10.g3 O-O 11.Bg2 Re8 12.O-O Na6 13.Rfd1 Nc7 14.Rac1 g6 15.e3 Bg7

up to 5…d5 as line 84

6.Bg5: The bishop pins the knight on f6. For Stockfish about a tenth weaker than 6.Qc2.
6…Be7: You break the pin. Stockfish chooses 6...Be7 (0) clearly ahead of 6...Nbd7 (+0.14).
7.Qa4: The queen goes to the diagonal a4–e8 and holds up Nbd7.
7…c6: The pawn closes the queen's diagonal. Stockfish had 7...Qd7 (-0.02) ahead; 7...c6 gives away seven hundredths and is the move of most players.
8.Bxf6: White trades on f6 and gives you the bishop pair – in return your pawn on d5 has one defender less.
8…Bxf6: Watch out: the exact move counts here. Stockfish rates 8...Bxf6 (+0.08) clearly ahead of 8...gxf6 (+1.58).
9.cxd5: White trades on d5 and fixes the structure – now you decide what to recapture with.
9…exd5: Watch out: the exact move counts here. Stockfish rates 9...exd5 (+0.07) clearly ahead of 9...b5 (+0.48).
10.g3: 10.g3 prepares the bishop on g2 – it is to press on the long diagonal against your pawn on d5.
10…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
11.Bg2: The bishop goes to g2 and presses on d5 – your pawn now needs protection.
11…Re8: Stockfish would have chosen 11...c5 (+0.1) here; 11...Re8 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
12.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
12…Na6: The knight goes to a6 and on to c7 – there it covers d5.
13.Rfd1: The rook goes to d1 behind the pawn on d4 and supports it for a later advance.
13…Nc7: The knight reaches c7 and covers d5 and e6.
14.Rac1: The rook goes to c1 and prepares b4.
14…g6: Stockfish would have chosen 14...Qe7 (+0.1) here; 14...g6 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
15.e3: 15.e3 supports d4 and opens the bishop on f1 – White plays quietly.
15…Bg7: The bishop goes to g7 and covers your king. Stockfish: level (+0.24).

Line 86: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.Qa4 c6 8.Bxf6 Bxf6 9.cxd5 exd5 10.g3 O-O 11.Bg2 Re8 12.O-O Na6 13.Rfd1 Nc7 14.e3 Qe7 15.Ne1 h5

up to 13…Nc7 as line 85

14.e3: 14.e3 supports d4 and closes your bishop's diagonal.
14…Qe7: The queen goes to e7 and connects the rooks.
15.Ne1: The knight goes to e1 and on to d3.
15…h5: 15...h5 gains space on the kingside and stops g4. Stockfish: level (+0.12).

Line 87: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.Qa4 c6 8.Bxf6 Bxf6 9.cxd5 exd5 10.g3 O-O 11.Bg2 Re8 12.O-O Na6 13.Rad1 c5 14.h4 Qc8 15.e3 Nc7

up to 12…Na6 as line 86

13.Rad1: The rook goes to d1 behind the pawn on d4 and supports it for a later advance.
13…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
14.h4: 14.h4 gains space on the kingside and threatens h5.
14…Qc8: The queen goes to c8 and eyes h3 and g4.
15.e3: 15.e3 supports d4 and opens the bishop on f1 – White plays quietly.
15…Nc7: The knight reaches c7 and covers d5 and e6. Stockfish: level (+0.18).

Line 88: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.Qa4 c6 8.Bxf6 Bxf6 9.cxd5 exd5 10.g3 O-O 11.Rd1 Bc8 12.Qc2 g6 13.Bg2 Bf5 14.e4 dxe4 15.Nxe4 Qe8

up to 10…O-O as line 87

11.Rd1: The rook goes to d1 behind the pawn on d4 and supports it for a later advance.
11…Bc8: The bishop goes back to c8 and on to f5 – it is more active there.
12.Qc2: The queen goes to c2 and prevents bishop to f5.
12…g6: 12...g6 prepares bishop to f5 – your bishop wants the b1–h7 diagonal.
13.Bg2: The bishop goes to g2 and presses on d5 – your pawn now needs protection.
13…Bf5: The bishop attacks the queen on c2 and gains a tempo.
14.e4: 14.e4 attacks your bishop on f5 and opens the centre.
14…dxe4: You take on e4 and open the position.
15.Nxe4: The knight recaptures and attacks your bishop on f6.
15…Qe8: The queen goes to e8 and attacks the knight on e4. Stockfish: level (0).

Line 89: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.Qa4 c6 8.Bxf6 Bxf6 9.e4 dxc4 10.Qxc4 Nd7 11.e5 Be7 12.Bd3 b5 13.Qb3 Rb8 14.Qd1 c5 15.Bxb5 O-O

up to 8…Bxf6 as line 88

9.e4: 9.e4 opens the centre and wants to use your lag in development.
9…dxc4: You take on c4 and win a pawn for the moment.
10.Qxc4: The queen recaptures on c4 and stands actively – but she is a target.
10…Nd7: The knight goes to d7 and covers e5 against the push.
11.e5: 11.e5 attacks your bishop on f6 and gains space.
11…Be7: The bishop retreats to e7 and covers d6.
12.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling.
12…b5: 12...b5 attacks the queen on c4 and gains space on the queenside.
13.Qb3: The queen steps aside to b3 and attacks your pawn on b5.
13…Rb8: The rook goes to b8 and supports the pawn on b5.
14.Qd1: The queen retreats to d1 and covers d4.
14…c5: 14...c5 attacks d4 and opens the position.
15.Bxb5: White takes the pawn on b5 – in return you get play against the centre.
15…O-O: You castle – for the pawn you have play against the centre. Stockfish: level (-0.02).

Line 90: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.Qa4 c6 8.cxd5 Nxd5 9.Bxe7 Nxc3 10.Qxc6 Nxc6 11.Bxd8 Nb5 12.Bg5 Nbxd4 13.Rd1 h6 14.Bf4 g5 15.Bg3 Nf5

up to 7…c6 as line 89

8.cxd5: White trades on d5 and fixes the structure – now you decide what to recapture with.
8…Nxd5: You recapture with the knight and attack the knight on c3.
9.Bxe7: White trades on e7 and attacks your queen.
9…Nxc3: You take on c3 first and attack the queen on a4 – an in-between move.
10.Qxc6: The queen takes on c6 – a sharp exchange in which a lot of material falls.
10…Nxc6: You take White's queen with the knight – yours will fall at once too.
11.Bxd8: White takes your queen on d8 back – material is level.
11…Nb5: The knight goes to b5 and attacks the pawn on d4.
12.Bg5: The bishop retreats to g5 and stays active.
12…Nbxd4: You take the pawn on d4 – a pawn up.
13.Rd1: The rook attacks your knight on d4 and covers the d-file.
13…h6: 13...h6 attacks the bishop on g5 and gains time.
14.Bf4: The bishop goes to f4 and eyes c7.
14…g5: 14...g5 attacks the bishop again and gains space.
15.Bg3: The bishop goes to g3 and eyes c7 and b8.
15…Nf5: The knight goes to f5 – a level endgame. Stockfish: level (0).

Line 91: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.e3 O-O 8.Rc1 Nbd7 9.cxd5 exd5 10.Bd3 c5 11.O-O Ne4 12.Bxe7 Qxe7 13.dxc5 bxc5 14.Qe2 Rfd8 15.Rfd1 Nxc3

up to 6…Be7 as line 90

7.e3: Stockfish's choice (+0.06): White develops the kingside.
7…O-O: The king first. Stockfish sees 7...O-O (+0.06) and 7...Nbd7 (+0.07) as equal.
8.Rc1: The rook goes to c1 onto the c-file, which will open after your c5.
8…Nbd7: The knight goes to d7 and supports c5 – later it can go to f6 or e4.
9.cxd5: White trades on d5 and fixes the structure – now you decide what to recapture with.
9…exd5: Watch out: the exact move counts here. Stockfish rates 9...exd5 (+0.03) clearly ahead of 9...Nxd5 (+0.59).
10.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling.
10…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
11.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
11…Ne4: The knight jumps to e4 and offers trades – with every piece traded you have fewer space problems.
12.Bxe7: White trades the dark bishops – your bishop on e7 was a good defender, but you lose nothing.
12…Qxe7: Watch out: the exact move counts here. Stockfish rates 12...Qxe7 (+0.25) clearly ahead of 12...Nxc3 (+5.47).
13.dxc5: White takes on c5 and gives you a choice: hanging pawns or a pawn less with active pieces.
13…bxc5: You recapture with the b-pawn and have the hanging pawns c5 and d5 – strong as long as they stay together.
14.Qe2: The queen goes to e2 and connects the rooks.
14…Rfd8: The rook goes to d8 and covers the pawn on d5.
15.Rfd1: The rook goes to d1 against the pawn on d5.
15…Nxc3: You trade on c3 – you stand slightly better. Stockfish: level (-0.11).

Line 92: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.e3 O-O 8.Rc1 Nbd7 9.cxd5 exd5 10.Bd3 c5 11.O-O Ne4 12.Bf4 Nxc3 13.Rxc3 c4 14.Bb1 b5 15.Ne5 Nxe5

up to 11…Ne4 as line 91

12.Bf4: The bishop goes to f4 and avoids the trade.
12…Nxc3: Watch out: the exact move counts here. Stockfish rates 12...Nxc3 (-0.37) clearly ahead of 12...Rc8 (+0.09).
13.Rxc3: The rook recaptures on c3 and stands on the third rank.
13…c4: Watch out: the exact move counts here. Stockfish rates 13...c4 (-0.39) clearly ahead of 13...Nf6 (+0.24).
14.Bb1: The bishop retreats to b1 and eyes h7.
14…b5: 14...b5 gains space on the queenside – your majority there rolls.
15.Ne5: The knight jumps to e5 and attacks your knight on d7.
15…Nxe5: You trade the knight on e5 – you stand better. Stockfish sees you ahead (-0.66).

Line 93: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.e3 O-O 8.Rc1 Nbd7 9.cxd5 exd5 10.Be2 c5 11.O-O Ne4 12.Bxe7 Qxe7 13.dxc5 Nxc3 14.Rxc3 bxc5 15.Qc2 Rac8

up to 9…exd5 as line 92

10.Be2: The bishop goes to e2 – modest but safe; it prepares castling.
10…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
11.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
11…Ne4: The knight jumps to e4 and offers trades – with every piece traded you have fewer space problems.
12.Bxe7: White trades the dark bishops – your bishop on e7 was a good defender, but you lose nothing.
12…Qxe7: You recapture with the queen; she stands actively on e7 and covers c5 and e5.
13.dxc5: White takes on c5 and gives you a choice: hanging pawns or a pawn less with active pieces.
13…Nxc3: You trade on c3 first and take White's knight.
14.Rxc3: The rook recaptures on c3 and attacks your pawn on c5.
14…bxc5: You recapture with the b-pawn and have the hanging pawns c5 and d5 – strong as long as they stay together.
15.Qc2: The queen goes to c2 and attacks the pawn on c5.
15…Rac8: The rook goes to c8 and covers the pawn on c5. Stockfish: level (+0.10).

Line 94: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.e3 O-O 8.Rc1 Nbd7 9.cxd5 exd5 10.Bb5 c6 11.Be2 Ne4 12.Bxe7 Qxe7 13.O-O Rfc8 14.h3 g6 15.Nd2 Nxc3

up to 9…exd5 as line 93

10.Bb5: The bishop pins your knight on d7 from b5.
10…c6: 10...c6 attacks the bishop and supports d5.
11.Be2: The bishop goes to e2 – modest but safe; it prepares castling.
11…Ne4: The knight jumps to e4 and offers trades – with every piece traded you have fewer space problems.
12.Bxe7: White trades the dark bishops – your bishop on e7 was a good defender, but you lose nothing.
12…Qxe7: You recapture with the queen; she stands actively on e7 and covers c5 and e5.
13.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
13…Rfc8: The rook goes to c8 onto the c-file and sets itself against White's rook.
14.h3: 14.h3 gives the king an escape square and takes g4 from your pieces.
14…g6: 14...g6 gives your king an escape square and takes f5 from White's pieces.
15.Nd2: The knight attacks your knight on e4.
15…Nxc3: You trade on c3 before White takes on e4 himself. Stockfish: level (+0.10).

Line 95: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.e3 O-O 8.Qc2 Nbd7 9.cxd5 exd5 10.Bd3 c5 11.Rd1 c4 12.Bf5 g6 13.Bxd7 Qxd7 14.Ne5 Qe6 15.O-O Rfe8

up to 7…O-O as line 94

8.Qc2: The queen goes to c2 and eyes h7.
8…Nbd7: Stockfish would have chosen 8...c5 (0) here; 8...Nbd7 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
9.cxd5: White trades on d5 and fixes the structure – now you decide what to recapture with.
9…exd5: Stockfish would have chosen 9...Nxd5 (0) here; 9...exd5 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
10.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling.
10…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
11.Rd1: The rook goes to d1 behind the pawn on d4 and supports it for a later advance.
11…c4: 11...c4 attacks the bishop on d3 and gains space.
12.Bf5: The bishop goes to f5 and attacks the knight on d7.
12…g6: 12...g6 drives the bishop from f5 and covers h7.
13.Bxd7: White trades on d7 and takes away one of your defenders.
13…Qxd7: You recapture with the queen; she connects the rooks.
14.Ne5: The knight jumps to e5 and attacks your queen on d7 – it gains a tempo.
14…Qe6: The queen goes to e6 and attacks the knight on e5.
15.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
15…Rfe8: The rook goes to the e-file against the knight on e5. Stockfish: level (+0.15).

Line 96: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.e3 O-O 8.cxd5 exd5 9.Bd3 Nbd7 10.O-O c5 11.Rc1

up to 7…O-O as line 95

8.cxd5: White trades on d5 and fixes the structure – now you decide what to recapture with.
8…exd5: You recapture with the pawn: you have a firm pawn on d5, and your bishop on b7 stands a little quiet behind it.
9.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling.
9…Nbd7: The knight goes to d7 and supports c5 – later it can go to f6 or e4.
10.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
10…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
11.Rc1: The rook goes to c1 onto the c-file, which will open after your c5. Stockfish: level (0). (transposition)

Line 97: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.e3 O-O 8.cxd5 exd5 9.Be2 Nbd7 10.O-O c5 11.dxc5 bxc5 12.Qb3 Qb6 13.Qxb6 axb6 14.Rfd1 Rfd8 15.Bb5 h6

up to 8…exd5 as line 96

9.Be2: The bishop goes to e2 – modest but safe; it prepares castling.
9…Nbd7: The knight goes to d7 and supports c5 – later it can go to f6 or e4.
10.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
10…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
11.dxc5: White takes on c5 and gives you a choice: hanging pawns or a pawn less with active pieces.
11…bxc5: You recapture with the b-pawn and have the hanging pawns c5 and d5 – strong as long as they stay together.
12.Qb3: The queen goes to b3 and attacks d5 and b7.
12…Qb6: The queen offers a queen trade – in the endgame the hanging pawns are easier to hold.
13.Qxb6: White trades queens and goes into the endgame.
13…axb6: You recapture with the a-pawn and open the a-file.
14.Rfd1: The rook goes to d1 against the pawn on d5.
14…Rfd8: The rook goes to d8 and covers the pawn on d5.
15.Bb5: The bishop attacks your knight on d7.
15…h6: 15...h6 attacks the bishop on g5 and gains time. Stockfish: level (+0.08).

Line 98: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.e3 O-O 8.cxd5 exd5 9.Rc1 Nbd7

up to 8…exd5 as line 97

9.Rc1: The rook goes to c1 onto the c-file, which will open after your c5.
9…Nbd7: The knight goes to d7 and supports c5 – later it can go to f6 or e4. Stockfish: level (+0.05). (transposition)

Line 99: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.e3 O-O 8.Bxf6 Bxf6 9.cxd5 exd5 10.Be2 c5 11.O-O Na6 12.Rc1 Nc7 13.dxc5 bxc5 14.Na4 c4 15.b3 Ne6

up to 7…O-O as line 98

8.Bxf6: White trades on f6 and gives you the bishop pair – in return your pawn on d5 has one defender less.
8…Bxf6: Watch out: the exact move counts here. Stockfish rates 8...Bxf6 (-0.04) clearly ahead of 8...gxf6 (+2.3).
9.cxd5: White trades on d5 and fixes the structure – now you decide what to recapture with.
9…exd5: You recapture with the pawn: you have a firm pawn on d5, and your bishop on b7 stands a little quiet behind it.
10.Be2: The bishop goes to e2 – modest but safe; it prepares castling.
10…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
11.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
11…Na6: The knight goes to a6 and on to c7.
12.Rc1: The rook goes to c1 onto the c-file, which will open after your c5.
12…Nc7: The knight reaches c7 and covers d5 and e6.
13.dxc5: White takes on c5 and gives you a choice: hanging pawns or a pawn less with active pieces.
13…bxc5: You recapture with the b-pawn and have the hanging pawns c5 and d5 – strong as long as they stay together.
14.Na4: The knight goes to a4 and attacks the pawn on c5.
14…c4: 14...c4 avoids the attack and gains space.
15.b3: 15.b3 attacks your pawn on c4 and wants to dissolve it.
15…Ne6: The knight goes to e6 and eyes d4 and g5 – level. Stockfish: level (0).

Line 100: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.e3 O-O 8.Bxf6 Bxf6 9.cxd5 exd5 10.Bd3 c5 11.O-O Nd7 12.Bb1 Rc8 13.Qc2 g6 14.Ba2 Re8 15.Bxd5 Bxd5

up to 9…exd5 as line 99

10.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling.
10…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
11.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
11…Nd7: The knight goes to d7 and covers c5 – it holds the pawn chain.
12.Bb1: The bishop goes to b1 and eyes h7.
12…Rc8: The rook goes to c8 and covers the pawn on c5.
13.Qc2: The queen goes to c2 and eyes h7.
13…g6: 13...g6 covers h7 against the queen-and-bishop battery.
14.Ba2: The bishop goes to a2 and attacks d5.
14…Re8: The rook goes to e8 onto the half-open e-file.
15.Bxd5: White takes the pawn on d5 and opens the long diagonal.
15…Bxd5: You recapture – material is level. Stockfish: level (+0.13).

Line 101: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.e3 O-O 8.Bxf6 Bxf6 9.cxd5 exd5 10.Qb3 Re8 11.Rd1 c6 12.Bd3 Nd7 13.O-O Nf8 14.e4 g6 15.Rfe1 Rc8

up to 9…exd5 as line 100

10.Qb3: The queen goes to b3 and attacks d5 and b7 – an annoying double attack.
10…Re8: Stockfish would have chosen 10...c5 (-0.12) here; 10...Re8 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
11.Rd1: The rook goes to d1 behind the pawn on d4 and supports it for a later advance.
11…c6: 11...c6 supports the pawn on d5 against the queen on b3.
12.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling.
12…Nd7: The knight goes to d7 and on to f8.
13.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
13…Nf8: Stockfish would have chosen 13...Rc8 (-0.04) here; 13...Nf8 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
14.e4: 14.e4 opens the centre for White's pieces.
14…g6: 14...g6 gives your king an escape square and takes f5 from White's pieces.
15.Rfe1: The rook goes to e1 and supports the pawn on e4.
15…Rc8: The rook goes to the c-file and eyes c3. Stockfish: level (+0.07).

Line 102: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.e3 O-O 8.Bd3 dxc4 9.Bxc4 c5 10.dxc5 Nbd7 11.Qe2 Nxc5 12.O-O h6 13.Bf4 a6 14.Rfd1 Qe8 15.Nd4 b5

up to 7…O-O as line 101

8.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling.
8…dxc4: You take on c4 – the bishop on d3 has to move a second time.
9.Bxc4: White recaptures with the bishop; it stands actively on c4.
9…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
10.dxc5: White takes on c5 and wins a pawn for the moment.
10…Nbd7: The knight goes to d7 and wins back the pawn.
11.Qe2: The queen goes to e2 and covers the pawn on c5.
11…Nxc5: You take back the pawn on c5 – material is level.
12.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
12…h6: 12...h6 gives your king an escape square and takes g5 from White's bishop.
13.Bf4: The bishop goes to f4 and eyes d6.
13…a6: 13...a6 prepares b5 with tempo against the bishop on c4.
14.Rfd1: The rook goes to d1 against your queen on d8.
14…Qe8: The queen goes to e8 off the d-file and away from the rook on d1.
15.Nd4: The knight jumps to d4 and eyes c6 and b5.
15…b5: 15...b5 attacks the bishop on c4 and gains space. Stockfish: level (0).

Line 103: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.Bxf6 Bxf6 8.cxd5 exd5 9.g3 O-O 10.Bg2 c5 11.O-O Na6 12.e3 Qe7 13.Re1 Nc7 14.Qc1 g6 15.Rb1 Rfe8

up to 6…Be7 as line 102

7.Bxf6: White gives the bishop for the knight.
7…Bxf6: Watch out: recapture with the bishop! 7...Bxf6 (+0.04) against 7...gxf6 (+1.91) – the pawn move tears open your king's position.
8.cxd5: White trades on d5 and fixes the structure – now you decide what to recapture with.
8…exd5: Watch out: the exact move counts here. Stockfish rates 8...exd5 (0) clearly ahead of 8...Bxd5 (+0.53).
9.g3: 9.g3 prepares the bishop on g2 – it is to press on the long diagonal against your pawn on d5.
9…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
10.Bg2: The bishop goes to g2 and presses on d5 – your pawn now needs protection.
10…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
11.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
11…Na6: The knight goes to a6 and on to c7.
12.e3: 12.e3 supports d4 and opens the bishop on f1 – White plays quietly.
12…Qe7: The queen goes to e7 and connects the rooks.
13.Re1: The rook goes to e1 and prepares e4.
13…Nc7: The knight reaches c7 and covers d5 and e6.
14.Qc1: The queen goes to c1 and eyes c5.
14…g6: 14...g6 gives your king an escape square and takes f5 from White's pieces.
15.Rb1: The rook goes to b1 and prepares b4.
15…Rfe8: The rook goes to the e-file against the pawn on e3. Stockfish: level (-0.03).

Line 104: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.Bxf6 Bxf6 8.cxd5 exd5 9.Qb3 O-O 10.Rd1 Re8 11.e3

up to 8…exd5 as line 103

9.Qb3: The queen goes to b3 and attacks d5 and b7 – an annoying double attack.
9…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
10.Rd1: The rook goes to d1 behind the pawn on d4 and supports it for a later advance.
10…Re8: Stockfish would have chosen 10...c5 (-0.14) here; 10...Re8 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
11.e3: 11.e3 supports d4 and opens the bishop on f1 – White plays quietly. Stockfish: level (-0.04). (transposition)

Line 105: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.Bxf6 Bxf6 8.cxd5 exd5 9.Qb3 O-O 10.Rd1 Re8 11.g3 c5

up to 10…Re8 as line 104

11.g3: 11.g3 is inaccurate – afterwards you stand better. Stockfish sees you ahead (-0.70).
11…c5: A move of Stockfish. Watch out: the exact move counts here. Stockfish rates 11...c5 (-0.75) clearly ahead of 11...Nc6 (0).

Line 106: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.Bxf6 Bxf6 8.cxd5 exd5 9.Qa4 c6

up to 8…exd5 as line 105

9.Qa4: The queen gives check on a4 and disturbs your castling.
9…c6: 9...c6 blocks the check and supports d5. Stockfish: level (+0.10). (transposition)

Line 107: 4.a3 Bb7 5.Nc3 d5 6.Bg5 Be7 7.Bxf6 Bxf6 8.cxd5 exd5 9.e3 O-O

up to 8…exd5 as line 106

9.e3: 9.e3 supports d4 and opens the bishop on f1 – White plays quietly.
9…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open. Stockfish: level (-0.04). (transposition)

Line 108: 4.a3 Bb7 5.Nc3 d5 6.Qc2 Be7 7.cxd5 exd5 8.Bf4 O-O 9.e3 c5 10.Bd3 c4 11.Be2 a6 12.Ne5 b5 13.Bf3 Nbd7 14.h4 Nb6 15.h5 h6

up to 5…d5 as line 107

6.Qc2: The queen prepares cxd5 and e4. Stockfish rates 6.Qc2 (+0.17) as its first choice.
6…Be7: You develop. Stockfish sees 6...c5 (+0.22) and 6...Be7 (+0.23) as equal.
7.cxd5: White trades on d5 and fixes the structure – now you decide what to recapture with.
7…exd5: Recapture with the pawn – you keep the centre. Stockfish had 7...Nxd5 (+0.17) ahead; 7...exd5 gives away a good tenth and is the move of half the players.
8.Bf4: The bishop goes to f4 and eyes c7.
8…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
9.e3: 9.e3 supports d4 and opens the bishop on f1 – White plays quietly.
9…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
10.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling.
10…c4: 10...c4 attacks the bishop on d3 and gains space on the queenside.
11.Be2: The bishop retreats to e2 and stays in the game.
11…a6: 11...a6 prepares b5 to support your pawn on c4.
12.Ne5: The knight jumps to e5 – a strong square in front of your king.
12…b5: 12...b5 supports the pawn on c4 – your majority on the queenside.
13.Bf3: The bishop goes to f3 and attacks your pawn on d5.
13…Nbd7: The knight attacks the knight on e5 and wants to trade it.
14.h4: 14.h4 attacks on the kingside – White's king is still in the centre.
14…Nb6: The knight goes to b6 and on to c4 or a4.
15.h5: 15.h5 gains space on the kingside and threatens h6.
15…h6: 15...h6 stops h6 and keeps the kingside closed. Stockfish: level (0).

Line 109: 4.a3 Bb7 5.Nc3 d5 6.Qc2 Be7 7.cxd5 exd5 8.g3 O-O 9.Bg2 c5 10.O-O Nbd7 11.Rd1 Rc8 12.dxc5 Nxc5 13.Ng5 g6 14.Bh3 Rc6 15.Bg2 Rc8

up to 7…exd5 as line 108

8.g3: 8.g3 prepares the bishop on g2 – it is to press on the long diagonal against your pawn on d5.
8…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
9.Bg2: The bishop goes to g2 and presses on d5 – your pawn now needs protection.
9…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
10…Nbd7: The knight goes to d7 and supports c5 – later it can go to f6 or e4.
11.Rd1: The rook goes to d1 behind the pawn on d4 and supports it for a later advance.
11…Rc8: The rook goes to c8 onto the c-file and sets itself against White's rook.
12.dxc5: White takes on c5 and leaves you an isolated pawn on d5.
12…Nxc5: You recapture with the knight; it stands actively on c5.
13.Ng5: The knight goes to g5 and eyes h7.
13…g6: 13...g6 gives your king an escape square and takes f5 from White's pieces.
14.Bh3: The bishop attacks your rook on c8 and gains a tempo.
14…Rc6: The rook goes to c6 and covers the knight on c5.
15.Bg2: The bishop returns to g2 and presses on d5.
15…Rc8: The rook goes back to c8 – White offers a repetition. Stockfish: level (+0.22). (transposition)

Line 110: 4.a3 Bb7 5.Nc3 d5 6.Qc2 Be7 7.cxd5 exd5 8.g3 O-O 9.Bh3 c5 10.O-O Nc6 11.Be3 Re8 12.Rad1 h6 13.dxc5 Bxc5 14.Nd4 Ne5 15.Bg2 Rc8

up to 8…O-O as line 109

9.Bh3: The bishop goes to h3 and avoids trading the light bishops – it eyes c8 and d7.
9…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal at the same time.
10…Nc6: The knight comes to c6 and attacks the pawn on d4.
11.Be3: The bishop goes to e3 and covers d4 against your knight.
11…Re8: The rook goes to e8 onto the half-open e-file against e3.
12.Rad1: The rook goes to d1 and supports the pawn on d4.
12…h6: 12...h6 gives your king an escape square and takes g5 from White's bishop.
13.dxc5: White takes on c5 and leaves you an isolated pawn on d5.
13…Bxc5: You recapture with the bishop; it attacks the bishop on e3.
14.Nd4: The knight jumps to d4 in front of your isolated pawn – an ideal blockade square.
14…Ne5: The knight goes to e5 and eyes c4 and g4.
15.Bg2: The bishop returns to g2 and presses on d5.
15…Rc8: The rook goes to c8 onto the c-file against the queen on c2. Stockfish: level (+0.10).

Line 111: 4.a3 Bb7 5.Nc3 d5 6.Qc2 Be7 7.cxd5 exd5 8.Bg5 O-O 9.e3 c5 10.Bd3 Nbd7

up to 7…exd5 as line 110

8.Bg5: The bishop pins your knight on f6 – the most important defender of d5 and e4.
8…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
9.e3: 9.e3 supports d4 and opens the bishop on f1.
9…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
10.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling.
10…Nbd7: The knight goes to d7 and supports c5 – later it can go to f6 or e4. Stockfish: level (+0.12). (transposition)

Chapter 3: 4.Nc3

Line 112: 4.Nc3 Bb7 5.a3

4.Nc3: The Kasparov Variation: White allows the pin Bb4. For Stockfish about a tenth weaker than 4.g3 and 4.a3.
4…Bb7: The bishop to the long diagonal. Stockfish had 4...Bb4 (+0.07) ahead; 4...Bb7 (+0.14) is the second choice. The players choose it in seven games out of ten – after 5.a3 it transposes to the Petrosian Variation.
5.a3: Transposition: this is the Petrosian Variation after 4.a3 4...Bb7 5.Nc3, where the course goes on. (transposition)

Line 113: 4.Nc3 Bb7 5.Bg5 h6 6.Bh4 Be7 7.e3 Ne4 8.Bxe7 Qxe7 9.Nxe4 Bxe4 10.Be2 O-O 11.O-O d6 12.Nd2 Bb7 13.Bf3 c5 14.Bxb7 Qxb7 15.Nf3 Rd8

up to 4…Bb7 as line 112

5.Bg5: The bishop pins the knight on f6 – for Stockfish almost two tenths weaker than 5.a3.
5…h6: You question the bishop at once. Stockfish sees 5...h6 and 5...Bb4 as equal (0).
6.Bh4: The bishop keeps the pin.
6…Be7: You break the pin. Stockfish sees 6...Bb4 (0) and 6...Be7 (+0.02) as equal.
7.e3: 7.e3 supports d4 and opens the bishop on f1.
7…Ne4: With the knight to e4 you trade pieces. Stockfish had 7...O-O (0) ahead; 7...Ne4 gives away a good two tenths but is the move of six out of ten players.
8.Bxe7: White trades the dark bishops – your bishop on e7 was a good defender, but you lose nothing.
8…Qxe7: Watch out: the exact move counts here. Stockfish rates 8...Qxe7 (-0.01) clearly ahead of 8...Kxe7 (+0.57).
9.Nxe4: White trades on e4 and simplifies the position.
9…Bxe4: Watch out: the exact move counts here. Stockfish rates 9...Bxe4 (+0.09) clearly ahead of 9...c5 (+7.02).
10.Be2: The bishop goes to e2 – modest but safe; it prepares castling.
10…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
11.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
11…d6: 11...d6 keeps e5 under control – in the set-up with e3 that is your firm base.
12.Nd2: The knight attacks your bishop on e4 and wants to drive it away.
12…Bb7: The bishop retreats to b7 and stays on the long diagonal.
13.Bf3: The bishop opposes your bishop on b7 and offers a trade.
13…c5: 13...c5 attacks d4 – the freeing move that gives your pieces room on the queenside.
14.Bxb7: White trades on b7 and takes your good bishop.
14…Qxb7: Watch out: the exact move counts here. Stockfish rates 14...Qxb7 (0) clearly ahead of 14...Nd7 (+7.86).
15.Nf3: The knight goes to f3 and covers d4 and e5.
15…Rd8: The rook goes to d8 and keeps d5 ready. Stockfish: level (0).

Line 114: 4.Nc3 Bb7 5.Bg5 h6 6.Bh4 Be7 7.e3 Ne4 8.Bxe7 Qxe7 9.Nxe4 Bxe4 10.Bd3 Qb4 11.Qd2 Qxd2 12.Kxd2 Bxd3 13.Kxd3 a5 14.b3 c5 15.Nd2 Na6

up to 9…Bxe4 as line 113

10.Bd3: The bishop attacks your bishop on e4 and offers a trade.
10…Qb4: The queen gives check on b4 and wants to trade queens.
11.Qd2: The queen blocks and offers a queen trade.
11…Qxd2: You trade queens – a quiet endgame without weaknesses.
12.Kxd2: The king recaptures and stands well in the centre.
12…Bxd3: You trade on d3 and take the last bishop.
13.Kxd3: The king recaptures and stands actively on d3.
13…a5: 13...a5 gains space on the queenside and takes b4 from White.
14.b3: 14.b3 supports the pawn on c4 and prepares a3 and b4.
14…c5: 14...c5 attacks d4 – the freeing move that gives your pieces room on the queenside.
15.Nd2: The knight goes to d2 and on to e4.
15…Na6: The knight goes to a6 and on to b4 – level. Stockfish: level (+0.03).

Line 115: 4.Nc3 Bb7 5.Bg5 h6 6.Bh4 Be7 7.e3 Ne4 8.Bxe7 Qxe7 9.Nxe4 Bxe4 10.Nd2 Bb7 11.Nb1 d6 12.Be2 Bxg2 13.Rg1 Bb7 14.Rxg7 Qf6 15.Rg3 Nd7

up to 9…Bxe4 as line 114

10.Nd2: The knight attacks your bishop on e4 and wants to drive it away.
10…Bb7: The bishop retreats to b7 and eyes g2.
11.Nb1: The knight goes back to b1 and on to c3 – a detour.
11…d6: 11...d6 keeps e5 under control – in the set-up with e3 that is your firm base.
12.Be2: The bishop goes to e2 – modest but safe; it prepares castling.
12…Bxg2: You take the pawn on g2 – White has left it undefended.
13.Rg1: The rook attacks your bishop on g2 and wants the pawn back.
13…Bb7: The bishop retreats to b7 and stays on the long diagonal.
14.Rxg7: The rook wins back the pawn on g7.
14…Qf6: The queen attacks the rook on g7 and drives it away.
15.Rg3: The rook retreats to g3 and covers the third rank.
15…Nd7: The knight goes to d7 and on to f6. Stockfish: level (0).

Line 116: 4.Nc3 Bb7 5.Bg5 h6 6.Bh4 Be7 7.e3 Ne4 8.Bxe7 Qxe7 9.Qc2 Nxc3 10.Qxc3 O-O 11.Be2 d6 12.O-O Nd7 13.b4 a5 14.a3 e5 15.h3 c5

up to 8…Qxe7 as line 115

9.Qc2: The queen goes to c2 and attacks your knight on e4.
9…Nxc3: You trade on c3 and take away one of White's defenders.
10.Qxc3: The queen recaptures on c3 and stands on the long diagonal.
10…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
11.Be2: The bishop goes to e2 – modest but safe; it prepares castling.
11…d6: 11...d6 keeps e5 under control – in the set-up with e3 that is your firm base.
12.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
12…Nd7: The knight goes to d7 and supports e5.
13.b4: 13.b4 gains space on the queenside and prepares b5 or c5.
13…a5: 13...a5 attacks the pawn on b4 and opens the a-file.
14.a3: 14.a3 supports the pawn on b4 and holds the queenside.
14…e5: 14...e5 attacks the centre and frees your position.
15.h3: 15.h3 gives White's king an escape square and takes g4 from your pieces.
15…c5: 15...c5 attacks d4 – the freeing move that gives your pieces room on the queenside. Stockfish: level (0).

Line 117: 4.Nc3 Bb7 5.Bg5 h6 6.Bh4 Be7 7.e3 Ne4 8.Bxe7 Qxe7 9.Rc1 Nxc3 10.Rxc3 d6 11.Bd3 c5 12.Bc2 Nd7 13.O-O Bxf3 14.Qxf3 O-O 15.dxc5 bxc5

up to 8…Qxe7 as line 116

9.Rc1: The rook goes to c1 and covers the knight on c3.
9…Nxc3: You trade on c3 and take away one of White's defenders.
10.Rxc3: The rook recaptures on c3 and stands actively.
10…d6: 10...d6 keeps e5 under control – in the set-up with e3 that is your firm base.
11.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling.
11…c5: 11...c5 attacks d4 – the freeing move that gives your pieces room on the queenside.
12.Bc2: The bishop goes to c2 and eyes h7.
12…Nd7: The knight goes to d7 and covers c5 and e5.
13.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
13…Bxf3: You trade on f3 and break up the castled position.
14.Qxf3: The queen recaptures and attacks your rook on a8.
14…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
15.dxc5: White takes on c5 and wants to give you hanging pawns.
15…bxc5: You recapture with the b-pawn and open the b-file. Stockfish: level (0).

Line 118: 4.Nc3 Bb7 5.Bg5 h6 6.Bh4 Be7 7.e3 Ne4 8.Nxe4 Bxe4 9.Bg3 O-O 10.Bd3 Bxd3 11.Qxd3 d6 12.O-O Nd7 13.h3 Qe8 14.Nd2 f5 15.Rae1 a6

up to 7…Ne4 as line 117

8.Nxe4: White trades on e4 and simplifies – your bishop recaptures.
8…Bxe4: You recapture with the bishop; it stands strongly on e4.
9.Bg3: The bishop goes to g3 and eyes c7.
9…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
10.Bd3: The bishop attacks your bishop on e4 and offers a trade.
10…Bxd3: You trade on d3 and avoid a retreat.
11.Qxd3: The queen recaptures on d3 and eyes h7.
11…d6: 11...d6 keeps e5 under control – in the set-up with e3 that is your firm base.
12.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
12…Nd7: The knight goes to d7 and supports e5.
13.h3: 13.h3 gives White's king an escape square and takes g4 from your pieces.
13…Qe8: The queen goes to e8 and on to g6 or h5.
14.Nd2: The knight goes to d2 and prepares e4.
14…f5: 14...f5 gains space and stops the push e4.
15.Rae1: The rook goes to e1 and prepares e4.
15…a6: 15...a6 prepares b5 and takes b5 from White. Stockfish: level (+0.21).

Line 119: 4.Nc3 Bb7 5.Bg5 h6 6.Bh4 Be7 7.e3 Ne4 8.Nxe4 Bxe4 9.Bg3 O-O 10.Nd2 Bb7 11.Bd3 d5 12.O-O c5 13.dxc5 bxc5 14.Re1 Nc6 15.cxd5 exd5

up to 9…O-O as line 118

10.Nd2: The knight attacks your bishop on e4 and wants to drive it away.
10…Bb7: The bishop retreats to b7 and stays on the long diagonal.
11.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling.
11…d5: 11...d5 attacks c4 and builds the centre.
12.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
12…c5: c5 is the freeing move: you attack d4 and get room for your pieces.
13.dxc5: White takes on c5 and opens the d-file – now it is decided who gets the open files.
13…bxc5: You recapture with the b-pawn and have the hanging pawns c5 and d5 – active, but a target.
14.Re1: The rook goes to e1 and prepares e4.
14…Nc6: The knight comes to c6 and covers d4 and e5.
15.cxd5: White trades on d5 and attacks the knight on c6.
15…exd5: You recapture with the pawn and hold the centre. Stockfish: level (+0.17).

Line 120: 4.Nc3 Bb7 5.Bg5 h6 6.Bh4 Be7 7.e3 Ne4 8.Bg3 Bb4 9.Qc2 c5 10.Be2 cxd4 11.exd4 Bxc3 12.bxc3 Nxg3 13.hxg3 Nc6 14.Rd1 Qc7 15.d5 Ne5

up to 7…Ne4 as line 119

8.Bg3: The bishop goes to g3 and avoids the trade.
8…Bb4: The bishop pins the knight on c3 and supports your knight on e4.
9.Qc2: The queen goes to c2 and attacks your knight on e4.
9…c5: 9...c5 attacks d4 and opens the position.
10.Be2: The bishop goes to e2 and prepares castling.
10…cxd4: You trade on d4 and open the c-file.
11.exd4: White recaptures with the e-pawn and opens the e-file.
11…Bxc3: You trade on c3 and give White doubled pawns.
12.bxc3: White recaptures with the pawn – the pawns on c3 and c4 are a target.
12…Nxg3: You trade on g3 and remove the bishop pair.
13.hxg3: White recaptures with the h-pawn and opens the h-file.
13…Nc6: The knight comes to c6 and attacks the pawn on d4.
14.Rd1: The rook goes to d1 and supports the pawn on d4.
14…Qc7: The queen goes to c7 and eyes g3 and c4.
15.d5: 15.d5 attacks the knight on c6 and gains space.
15…Ne5: The knight jumps to e5 and attacks the knight on f3. Stockfish: level (+0.12).

Line 121: 4.Nc3 Bb7 5.Bg5 h6 6.Bh4 Be7 7.Qc2 c5 8.dxc5 bxc5 9.e3 O-O 10.Be2 d6 11.O-O Nbd7 12.Rfd1 Qb6 13.Rd2 Rfd8 14.Rad1 a6 15.h3 Qc7

up to 6…Be7 as line 120

7.Qc2: The queen goes to c2 and eyes h7 with the bishop on d3 – and covers e4.
7…c5: The lever against d4. Stockfish sees 7...c5 and 7...d5 as equal (+0.04).
8.dxc5: White takes on c5 and wants to give you doubled pawns.
8…bxc5: You recapture with the b-pawn and open the b-file.
9.e3: 9.e3 supports c4 and opens the bishop on f1.
9…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
10.Be2: The bishop goes to e2 and prepares castling.
10…d6: 10...d6 – the Hedgehog: you hold e5 and c5 and wait for your chance.
11.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
11…Nbd7: The knight goes to d7 and supports e5 or c5 – your two freeing moves.
12.Rfd1: The rook goes to d1 against your pawn on d6.
12…Qb6: The queen goes to b6 and eyes b2.
13.Rd2: The rook goes to d2 and wants to double the rooks.
13…Rfd8: The rook goes to d8 and covers the pawn on d6.
14.Rad1: The rook doubles on the d-file against d6.
14…a6: Stockfish would have chosen 14...Nf8 (0) here; 14...a6 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
15.h3: 15.h3 gives White's king an escape square and takes g4 from your pieces.
15…Qc7: The queen goes to c7 and covers the pawn on d6. Stockfish: level (+0.23).

Line 122: 4.Nc3 Bb7 5.Bg5 h6 6.Bh4 Be7 7.Qc2 c5 8.e4 g5 9.Bg3 g4 10.Nd2 cxd4 11.Nb5 d6 12.Nxd4 Nh5 13.Be2 Nxg3 14.hxg3 Bf6 15.Qd3 h5

up to 7…c5 as line 121

8.e4: 8.e4 builds the centre, but the bishop on h4 stands offside.
8…g5: 8...g5 attacks the bishop on h4 and gains space – you already stand better.
9.Bg3: The bishop retreats to g3 and eyes b8.
9…g4: 9...g4 attacks the knight on f3 and drives it from the centre.
10.Nd2: The knight steps aside to d2 and covers e4.
10…cxd4: You take on d4 and win a pawn.
11.Nb5: The knight jumps to b5 and attacks d4.
11…d6: 11...d6 covers c7 and e5 against the knight on b5.
12.Nxd4: White wins back the pawn on d4 – material is level.
12…Nh5: The knight attacks the bishop on g3 and wants the bishop pair.
13.Be2: The bishop goes to e2 and attacks the pawn on g4.
13…Nxg3: You trade on g3 and get the bishop pair.
14.hxg3: White recaptures with the h-pawn and opens the h-file for his rook.
14…Bf6: The bishop attacks the knight on d4 and stands on the long diagonal.
15.Qd3: The queen goes to d3 and covers the knight on d4.
15…h5: 15...h5 gains space – you stand slightly better. Stockfish: level (-0.09).

Line 123: 4.Nc3 Bb7 5.Bg5 h6 6.Bxf6 Qxf6 7.e3 Bb4 8.Rc1 Bxc3 9.Rxc3 d6 10.Be2 O-O 11.O-O a5 12.Nd2 e5 13.dxe5 dxe5 14.c5 Qg6 15.f3 Na6

up to 5…h6 as line 122

6.Bxf6: White gives the bishop at once.
6…Qxf6: Recapture with the queen! 6...Qxf6 (-0.04) against 6...gxf6 (+0.64).
7.e3: 7.e3 supports d4 and opens the bishop on f1.
7…Bb4: A move of Stockfish: the pin on c3. Stockfish sees 7...Bb4 and 7...g6 as equal (0).
8.Rc1: The rook goes to c1 and covers the knight on c3.
8…Bxc3: You trade on c3 – with queen and bishop on b7 you press on the centre.
9.Rxc3: The rook recaptures on c3 and stands actively on the third rank.
9…d6: 9...d6 prepares e5 – your queen on f6 supports the push.
10.Be2: The bishop goes to e2 and prepares castling.
10…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
11.O-O: White castles short and brings the king to safety; the rook on f1 comes to d1 or c1.
11…a5: 11...a5 gains space on the queenside and takes b4 from White.
12.Nd2: The knight goes to d2 and on to e4.
12…e5: 12...e5 attacks the centre – the freeing move.
13.dxe5: White takes on e5 and opens the d-file.
13…dxe5: You recapture and have a strong pawn on e5.
14.c5: 14.c5 opens the diagonal of the bishop on e2.
14…Qg6: The queen goes to g6 and attacks the pawn on g2.
15.f3: 15.f3 covers g2 and e4 against your queen.
15…Na6: The knight goes to a6 and on to c5. Stockfish: level (0).

Chapter 4: 4.e3

Line 124: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.Nc3 O-O 8.b3 Nbd7 9.Bb2 a6 10.Rc1 Qe7 11.Na4 dxc4 12.bxc4 c5 13.Ne5 Bc7 14.Qe2 Rfd8 15.f4 Nf8

4.e3: The Spassky System: White sets up calmly with Bd3 and O-O. For Stockfish about a tenth weaker than 4.g3.
4…Bb7: The bishop to the long diagonal. Stockfish had 4...d5 (+0.07) just ahead; the players choose 4...Bb7 in almost every game.
5.Bd3: Stockfish's choice (+0.11): the bishop aims at h7.
5…d5: You occupy the centre. Stockfish chooses 5...d5 (+0.06) clearly ahead of 5...a6 (+0.19).
6.O-O: White castles. Stockfish sees 6.Nc3 (+0.06) and 6.O-O (+0.04) as equal.
6…Bd6: The bishop aims at h2. Stockfish had 6...dxc4 (+0.04) ahead; 6...Bd6 (+0.13) gives away just under a tenth and is the move of half the players.
7.Nc3: White develops. Stockfish would have played 7.b3 (+0.13).
7…O-O: Stockfish chooses 7...O-O (+0.02) ahead of 7...dxc4 (+0.11).
8.b3: b3 prepares the bishop on b2 – White aims both bishops at your kingside.
8…Nbd7: The knight goes to d7 and supports e5 or c5 – your two freeing moves.
9.Bb2: The bishop goes to b2 onto the long diagonal – it watches e5 and c5.
9…a6: a6 takes b5 from White and prepares b5 or c5.
10.Rc1: The rook goes to c1 onto the c-file, where play arises after cxd5 or c5.
10…Qe7: The queen goes to e7 and connects the rooks; she covers c5 and e5.
11.Na4: The knight goes to a4 and eyes c5 and b6.
11…dxc4: You take on c4 and open the diagonal of your bishop on b7.
12.bxc4: White recaptures with the b-pawn and gets hanging pawns on c4 and d4.
12…c5: 12...c5 attacks d4 – the freeing move that gives your pieces room on the queenside.
13.Ne5: The knight jumps to e5 and attacks your knight on d7.
13…Bc7: The bishop goes to c7 and attacks the knight on e5.
14.Qe2: The queen goes to e2 and connects the rooks.
14…Rfd8: The rook goes to d8 against the pawn on d4.
15.f4: 15.f4 supports the knight on e5 – White builds a Stonewall.
15…Nf8: The knight goes to f8 and covers h7 against the attack. Stockfish: level (0).

Line 125: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.Nc3 O-O 8.b3 Nbd7 9.Bb2 a6 10.Rc1 Qe7 11.cxd5 exd5 12.Ne2 Ne4 13.Ng3 Nxg3 14.hxg3 Nf6 15.Ne5 a5

up to 10…Qe7 as line 124

11.cxd5: White trades on d5 and fixes the structure.
11…exd5: You recapture with the pawn and hold the centre.
12.Ne2: The knight goes to e2 and on to g3.
12…Ne4: The knight jumps to e4 – an outpost White can hardly drive it from without f3.
13.Ng3: The knight attacks your knight on e4 and wants to trade it – the outpost bothers White.
13…Nxg3: You trade on g3 before White takes on e4 himself – your structure stays healthy.
14.hxg3: White recaptures with the h-pawn and opens the h-file for his rook.
14…Nf6: The knight returns to f6 and covers the kingside.
15.Ne5: The knight jumps to e5 and eyes c6 and d7.
15…a5: 15...a5 gains space – you stand slightly better. Stockfish: level (-0.14).

Line 126: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.Nc3 O-O 8.b3 Nbd7 9.Bb2 a6 10.Rc1 Qe7 11.cxd5 exd5 12.Ne2 Ne4 13.Qc2 Rac8 14.Ng3 Nxg3 15.hxg3 Nf6

up to 12…Ne4 as line 125

13.Qc2: The queen goes to c2 and eyes h7 with the bishop on d3 – she also covers e4.
13…Rac8: The rook goes to c8 against the queen on c2.
14.Ng3: The knight attacks your knight on e4 and wants to trade it – the outpost bothers White.
14…Nxg3: You trade on g3 before White takes on e4 himself – your structure stays healthy.
15.hxg3: White recaptures with the h-pawn and opens the h-file for his rook.
15…Nf6: The knight returns to f6 – you stand slightly better. Stockfish: level (-0.18).

Line 127: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.Nc3 O-O 8.b3 Nbd7 9.Bb2 a6 10.Rc1 Qe7 11.Qe2 Ne4 12.a4 f5 13.a5 dxc4 14.bxc4 Rf6 15.Bb1 Rg6

up to 10…Qe7 as line 126

11.Qe2: The queen goes to e2 and connects the rooks; she covers c4 and e4 and prepares e4.
11…Ne4: The knight jumps to e4 – an outpost White can hardly drive it from without f3.
12.a4: 12.a4 gains space on the queenside and threatens a5 against your pawn on b6.
12…f5: f5 supports the knight on e4 – the Stonewall set-up: you hold e4 and can attack on the kingside.
13.a5: 13.a5 attacks your pawn on b6 and wants to open the a-file.
13…dxc4: You take on c4 and open the diagonal of your bishop on b7.
14.bxc4: White recaptures with the b-pawn and has hanging pawns on c4 and d4.
14…Rf6: The rook goes to f6 and on to g6 or h6 – an attack on the king.
15.Bb1: The bishop goes to b1 and covers e4 against your knight.
15…Rg6: The rook goes to g6 and attacks the pawn on g2. Stockfish: level (0).

Line 128: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.Nc3 O-O 8.b3 Nbd7 9.Bb2 a6 10.Qe2 Ne4 11.Rac1 f5 12.a4 Qf6 13.a5 Qh6 14.h3 Rf6 15.cxd5 Nxc3

up to 9…a6 as line 127

10.Qe2: The queen goes to e2 and connects the rooks; she covers c4 and e4 and prepares e4.
10…Ne4: Stockfish would have chosen 10...dxc4 (0) here; 10...Ne4 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
11.Rac1: The rook goes to c1 onto the c-file – it will open after c5 or cxd5.
11…f5: f5 supports the knight on e4 – the Stonewall set-up: you hold e4 and can attack on the kingside.
12.a4: 12.a4 gains space on the queenside and threatens a5 against your pawn on b6.
12…Qf6: The queen goes to f6 and on to h6 – an attack on the kingside.
13.a5: 13.a5 attacks your pawn on b6 and wants to open the a-file.
13…Qh6: The queen goes to h6 and eyes h2.
14.h3: 14.h3 covers g4 against your pieces and gives the king air.
14…Rf6: The rook goes to f6 and on to g6 – an attack on g2.
15.cxd5: White trades on d5 and opens the position.
15…Nxc3: You trade on c3 and keep the attack. Stockfish: level (0).

Line 129: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.Nc3 O-O 8.b3 Nbd7 9.Bb2 a6 10.Qe2 Ne4 11.Rad1 Qe7 12.Qc2 f5 13.Ne2 Rf6 14.c5 bxc5 15.dxc5 Nexc5

up to 10…Ne4 as line 128

11.Rad1: The rook goes to d1 and supports the pawn on d4.
11…Qe7: The queen goes to e7 and connects the rooks; she covers c5 and e5.
12.Qc2: The queen goes to c2 and eyes h7 with the bishop on d3 – she also covers e4.
12…f5: f5 supports the knight on e4 – the Stonewall set-up: you hold e4 and can attack on the kingside.
13.Ne2: The knight goes to e2 and on to f4.
13…Rf6: The rook goes to f6 and on to h6 – an attack on h2.
14.c5: 14.c5 attacks your bishop on d6 and gains space.
14…bxc5: You take on c5 and open the position.
15.dxc5: White recaptures and attacks your bishop on d6.
15…Nexc5: You take the pawn on c5 with the knight. Stockfish: level (+0.07).

Line 130: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.Nc3 O-O 8.b3 Nbd7 9.Bb2 a6 10.Qc2 dxc4 11.bxc4 Bxf3 12.gxf3 c5 13.Rfd1 cxd4 14.Ne4 Nc5 15.Bxd4 Nfxe4

up to 9…a6 as line 129

10.Qc2: The queen goes to c2 and eyes h7 with the bishop on d3 – and covers e4.
10…dxc4: You take on c4 and open the diagonal of your bishop on b7.
11.bxc4: White recaptures with the b-pawn and has hanging pawns on c4 and d4.
11…Bxf3: You trade on f3 and break up the castled position.
12.gxf3: White recaptures with the g-pawn – the king stands more exposed.
12…c5: 12...c5 attacks d4 – the freeing move that gives your pieces room on the queenside.
13.Rfd1: The rook goes to d1 and supports the pawn on d4.
13…cxd4: You take on d4 and win a pawn for the moment.
14.Ne4: The knight attacks the knight on f6 and the bishop on d6.
14…Nc5: The knight attacks the knight on e4 and the bishop on d3.
15.Bxd4: White takes back the pawn on d4 and attacks your knight.
15…Nfxe4: You take on e4 and simplify – level. Stockfish: level (0).

Line 131: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.Nc3 O-O 8.cxd5 exd5 9.b3 a6 10.Bb2 Nbd7 11.Rc1 Qe7

up to 7…O-O as line 130

8.cxd5: White trades on d5 and fixes the structure.
8…exd5: Watch out: the exact move counts here. Stockfish rates 8...exd5 (0) clearly ahead of 8...Nxd5 (+0.54).
9.b3: b3 prepares the bishop on b2 – White aims both bishops at your kingside.
9…a6: a6 takes b5 from White and prepares b5 or c5.
10.Bb2: The bishop goes to b2 onto the long diagonal – it watches e5 and c5.
10…Nbd7: The knight goes to d7 and supports e5 or c5 – your two freeing moves.
11.Rc1: The rook goes to c1 onto the c-file, where play arises after cxd5 or c5.
11…Qe7: The queen goes to e7 and connects the rooks; she covers c5 and e5. Stockfish: level (0). (transposition)

Line 132: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.Nc3 O-O 8.cxd5 exd5 9.b3 a6 10.Bb2 Nbd7 11.Ne2 Qe7 12.Ng3 g6 13.Rc1 Ne4 14.Rc2 a5 15.Ne2 c6

up to 10…Nbd7 as line 131

11.Ne2: The knight goes to e2 and on to g3.
11…Qe7: The queen goes to e7 and connects the rooks; she covers c5 and e5.
12.Ng3: The knight reaches g3 and eyes f5 and e4.
12…g6: Watch out: the exact move counts here. Stockfish rates 12...g6 (-0.02) clearly ahead of 12...Bxg3 (+0.65).
13.Rc1: The rook goes to c1 onto the c-file – it will open after c5 or cxd5.
13…Ne4: The knight jumps to e4 – an outpost White can hardly drive it from without f3.
14.Rc2: The rook goes to c2 and wants to double the rooks.
14…a5: 14...a5 gains space on the queenside and takes b4 from White.
15.Ne2: The knight goes to e2 and on to f4.
15…c6: 15...c6 supports d5 – you stand slightly better. Stockfish: level (-0.12).

Line 133: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.Nc3 O-O 8.cxd5 exd5 9.Qc2 c5 10.b3 Re8 11.Bb2 Nc6 12.a3 cxd4 13.exd4 Ne4 14.Nxe4 dxe4 15.Bxe4 Nxd4

up to 8…exd5 as line 132

9.Qc2: The queen goes to c2 and eyes h7 with the bishop on d3 – and covers e4.
9…c5: 9...c5 attacks d4 – the freeing move that gives your pieces room on the queenside.
10.b3: b3 prepares the bishop on b2 – White aims both bishops at your kingside.
10…Re8: The rook goes to the half-open e-file against e3.
11.Bb2: The bishop goes to b2 onto the long diagonal – it watches e5 and c5.
11…Nc6: The knight comes to c6 and attacks the pawn on d4.
12.a3: 12.a3 takes b4 away from your knight.
12…cxd4: You take on d4 and open the position.
13.exd4: White recaptures with the e-pawn and opens the e-file.
13…Ne4: The knight jumps to e4 – an outpost White can hardly drive it from without f3.
14.Nxe4: White trades on e4 and opens his bishop's diagonal.
14…dxe4: You recapture with the pawn and attack the bishop on d3.
15.Bxe4: White takes the pawn on e4 and attacks your knight on c6.
15…Nxd4: You take the pawn on d4 – material is level. Stockfish: level (0).

Line 134: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.Nc3 O-O 8.Qe2 Ne4 9.Qc2 Nxc3 10.bxc3 h6 11.cxd5 exd5 12.Bb2 Nd7 13.Qe2 Re8 14.Rfd1 Qf6 15.c4 dxc4

up to 7…O-O as line 133

8.Qe2: The queen goes to e2 and connects the rooks; she covers c4 and e4 and prepares e4.
8…Ne4: Stockfish would have chosen 8...c5 (-0.04) here; 8...Ne4 gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
9.Qc2: The queen goes to c2 and eyes h7 with the bishop on d3 – and covers e4.
9…Nxc3: You trade on c3 and give White doubled pawns.
10.bxc3: White recaptures with the pawn and strengthens d4.
10…h6: 10...h6 gives your king an escape square and takes g5 from White's bishop.
11.cxd5: White trades on d5 and fixes the structure.
11…exd5: You recapture and hold the centre.
12.Bb2: The bishop goes to b2 onto the long diagonal – it watches e5 and c5.
12…Nd7: The knight goes to d7 and on to f6.
13.Qe2: The queen goes to e2 and connects the rooks; she covers c4 and e4 and prepares e4.
13…Re8: The rook goes to the half-open e-file against e3.
14.Rfd1: The rook goes to d1 and supports the pawn on d4.
14…Qf6: The queen attacks the knight on f3 and eyes c3.
15.c4: 15.c4 opens the diagonal of the bishop on b2.
15…dxc4: You take on c4 and open the position. Stockfish: level (+0.24).

Line 135: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.Nc3 O-O 8.Qc2 dxc4 9.Bxc4 c5 10.dxc5 Bxc5 11.b3 Nbd7 12.Bb2 Qe7 13.Rac1 Rfd8 14.Be2 Rac8 15.h3 Bd6

up to 7…O-O as line 134

8.Qc2: The queen goes to c2 and eyes h7 with the bishop on d3 – and covers e4.
8…dxc4: You take on c4 – the bishop on d3 has to move a second time.
9.Bxc4: White recaptures with the bishop; it stands actively on c4.
9…c5: 9...c5 attacks d4 – the freeing move that gives your pieces room on the queenside.
10.dxc5: White takes on c5 and attacks your bishop on d6.
10…Bxc5: You recapture with the bishop; it stands actively on c5.
11.b3: b3 prepares the bishop on b2 – White aims both bishops at your kingside.
11…Nbd7: The knight goes to d7 and supports e5 or c5 – your two freeing moves.
12.Bb2: The bishop goes to b2 onto the long diagonal – it watches e5 and c5.
12…Qe7: The queen goes to e7 and connects the rooks; she covers c5 and e5.
13.Rac1: The rook goes to c1 onto the c-file – it will open after c5 or cxd5.
13…Rfd8: The rook goes to d8 onto the open d-file.
14.Be2: The bishop goes to e2 and covers d3 against your pieces.
14…Rac8: The rook goes to c8 against the rook on c1.
15.h3: 15.h3 gives White's king an escape square and takes g4 from your pieces.
15…Bd6: The bishop goes to d6 and eyes h2. Stockfish: level (-0.02).

Line 136: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.b3 O-O 8.Bb2 Nbd7 9.Nc3

up to 6…Bd6 as line 135

7.b3: Stockfish's choice (+0.13): the bishop on c1 is heading for b2.
7…O-O: Stockfish sees 7...Nbd7 (+0.04) and 7...O-O (+0.05) as equal.
8.Bb2: The bishop goes to b2 onto the long diagonal – it watches e5 and c5.
8…Nbd7: The knight goes to d7 and supports e5 or c5 – your two freeing moves.
9.Nc3: The knight goes to c3 and presses on d5 and e4. Stockfish: level (+0.06). (transposition)

Line 137: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.b3 O-O 8.Bb2 Nbd7 9.Nbd2 Ne4 10.Qc2 f5 11.cxd5 Nxd2 12.Qxd2 Bxd5 13.Qe2 Qf6 14.Bc4 Bb7 15.a4 Qh6

up to 8…Nbd7 as line 136

9.Nbd2: The knight goes to d2 and attacks your knight on e4.
9…Ne4: The knight jumps to e4 – an outpost White can hardly drive it from without f3.
10.Qc2: The queen goes to c2 and eyes h7 with the bishop on d3 – she also covers e4.
10…f5: f5 supports the knight on e4 – the Stonewall set-up: you hold e4 and can attack on the kingside.
11.cxd5: White trades on d5 and opens the position.
11…Nxd2: You trade on d2 first – an in-between move.
12.Qxd2: The queen recaptures on d2 and stands on the d-file.
12…Bxd5: You take back the pawn on d5 with the bishop.
13.Qe2: The queen goes to e2 and connects the rooks; she covers c4 and e4 and prepares e4.
13…Qf6: The queen goes to f6 and on to h6.
14.Bc4: The bishop attacks your bishop on d5 and wants to trade it.
14…Bb7: The bishop retreats to b7 and avoids the trade.
15.a4: 15.a4 gains space on the queenside and threatens a5 against your pawn on b6.
15…Qh6: The queen goes to h6 and eyes h2. Stockfish: level (0).

Line 138: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.b3 O-O 8.Bb2 Nbd7 9.Nbd2 Ne4 10.Qe2 Qe7 11.Rfd1 a5 12.Ne5 Nxe5 13.dxe5 Bb4 14.Nxe4 dxe4 15.Bc2 Ba3

up to 9…Ne4 as line 137

10.Qe2: The queen goes to e2 and connects the rooks; she covers c4 and e4 and prepares e4.
10…Qe7: The queen goes to e7 and connects the rooks; she covers c5 and e5.
11.Rfd1: The rook goes to d1 and supports the pawn on d4.
11…a5: 11...a5 gains space on the queenside and takes b4 from White.
12.Ne5: The knight jumps to e5 and attacks your knight on d7.
12…Nxe5: You trade on e5 and take White's strong knight.
13.dxe5: White recaptures and attacks your bishop on d6.
13…Bb4: The bishop goes to b4 and attacks the knight on d2.
14.Nxe4: White trades on e4 and simplifies the position.
14…dxe4: You recapture and attack the bishop on d3.
15.Bc2: The bishop retreats to c2 and covers e4.
15…Ba3: The bishop offers a trade against the bishop on b2. Stockfish: level (0).

Line 139: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.b3 O-O 8.Bb2 Nbd7 9.Nbd2 Ne4 10.Rc1 Rc8 11.Qc2 Ndf6 12.h3 Nxd2 13.Nxd2 c5 14.dxc5 Bxc5 15.Rfd1 h6

up to 9…Ne4 as line 138

10.Rc1: The rook goes to c1 onto the c-file – it will open after c5 or cxd5.
10…Rc8: The rook goes to c8 against the rook on c1.
11.Qc2: The queen goes to c2 and eyes h7 with the bishop on d3 – she also covers e4.
11…Ndf6: The knight goes to f6 and supports the knight on e4.
12.h3: 12.h3 gives White's king an escape square and takes g4 from your pieces.
12…Nxd2: You trade on d2 and take away one of White's defenders.
13.Nxd2: The knight recaptures on d2 and covers c4 and e4.
13…c5: 13...c5 attacks d4 – the freeing move that gives your pieces room on the queenside.
14.dxc5: White takes on c5 and opens the position.
14…Bxc5: You recapture with the bishop; it stands actively.
15.Rfd1: The rook goes to d1 onto the open d-file.
15…h6: 15...h6 gives your king an escape square and takes g5 from White's bishop. Stockfish: level (+0.02).

Line 140: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.b3 O-O 8.Bb2 Nbd7 9.Ne5 c5 10.Nd2 cxd4 11.exd4 dxc4 12.Ndxc4 Be7 13.Qe2 Nd5 14.Nxd7 Qxd7 15.Ne5 Qd6

up to 8…Nbd7 as line 139

9.Ne5: The knight jumps to e5 and attacks your knight on d7.
9…c5: 9...c5 attacks d4 – the freeing move that gives your pieces room on the queenside.
10.Nd2: The knight goes to d2 and covers c4 and e4.
10…cxd4: You take on d4 and open the position.
11.exd4: White recaptures with the e-pawn and opens the e-file.
11…dxc4: You take on c4 and open your bishop's diagonal.
12.Ndxc4: The knight recaptures and attacks your bishop on d6.
12…Be7: The bishop retreats to e7 and covers the kingside.
13.Qe2: The queen goes to e2 and connects the rooks; she covers c4 and e4 and prepares e4.
13…Nd5: The knight jumps to d5 in front of the isolated pawn on d4.
14.Nxd7: White trades on d7 and takes away one of your defenders.
14…Qxd7: The queen recaptures on d7; she connects the rooks but stands in the knight's way.
15.Ne5: The knight jumps to e5 and attacks your queen on d7 – it gains a tempo.
15…Qd6: The queen goes to d6 – you stand slightly better. Stockfish: level (-0.14).

Line 141: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.b3 O-O 8.Bb2 Nbd7 9.Qe2 c5 10.Ne5 Rc8 11.Nd2 Ne4 12.Ndf3 Qe7 13.Nxd7 Qxd7 14.cxd5 exd5 15.Ne5 Qe7

up to 8…Nbd7 as line 140

9.Qe2: The queen goes to e2 and connects the rooks; she covers c4 and e4 and prepares e4.
9…c5: 9...c5 attacks d4 – the freeing move that gives your pieces room on the queenside.
10.Ne5: The knight jumps to e5 and attacks your knight on d7.
10…Rc8: The rook goes to c8 onto the c-file and sets itself against White's rook.
11.Nd2: The knight goes to d2 and covers c4 and e4.
11…Ne4: The knight jumps to e4 – an outpost White can hardly drive it from without f3.
12.Ndf3: The knight goes to f3 and supports the knight on e5.
12…Qe7: The queen goes to e7 and connects the rooks; she covers c5 and e5.
13.Nxd7: White trades on d7 and takes away one of your defenders.
13…Qxd7: The queen recaptures on d7; she connects the rooks but stands in the knight's way.
14.cxd5: White trades on d5 and opens the position.
14…exd5: You recapture and hold the centre.
15.Ne5: The knight jumps to e5 and attacks your queen on d7 – it gains a tempo.
15…Qe7: The queen goes to e7 and attacks the knight on e5. Stockfish: level (0).

Line 142: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.b3 O-O 8.Nc3

up to 7…O-O as line 141

8.Nc3: The knight goes to c3 and presses on d5 and e4. Stockfish: level (+0.05). (transposition)

Line 143: 4.e3 Bb7 5.Bd3 d5 6.O-O Bd6 7.b4 dxc4 8.Bxc4 O-O 9.a3 Nbd7 10.Bb2 Ne4 11.Nc3 Nxc3 12.Bxc3 a5 13.bxa5 bxa5 14.Qe2 Qe7 15.a4 c5

up to 6…Bd6 as line 142

7.b4: White attacks on the queenside – for Stockfish almost a quarter of a pawn weaker than 7.b3.
7…dxc4: You take the pawn on c4. Stockfish chooses 7...dxc4 (-0.1) clearly ahead of 7...a5 (+0.38).
8.Bxc4: White recaptures with the bishop; it stands actively on c4.
8…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
9.a3: 9.a3 supports the pawn on b4 and holds the queenside.
9…Nbd7: The knight goes to d7 and supports e5 or c5 – your two freeing moves.
10.Bb2: The bishop goes to b2 onto the long diagonal – it watches e5 and c5.
10…Ne4: The knight jumps to e4 – an outpost White can hardly drive it from without f3.
11.Nc3: The knight attacks your knight on e4.
11…Nxc3: You trade on c3 and take away one of White's defenders.
12.Bxc3: The bishop recaptures on c3 and stands on the long diagonal.
12…a5: 12...a5 attacks the pawn on b4 and opens the a-file.
13.bxa5: White takes on a5 and opens the a-file.
13…bxa5: You recapture and open the b-file.
14.Qe2: The queen goes to e2 and connects the rooks; she covers c4 and e4 and prepares e4.
14…Qe7: The queen goes to e7 and connects the rooks; she covers c5 and e5.
15.a4: 15.a4 gains space on the queenside and fixes your pawn on a5.
15…c5: 15...c5 attacks d4 – the freeing move that gives your pieces room on the queenside. Stockfish: level (+0.10).

Line 144: 4.e3 Bb7 5.Bd3 d5 6.b3 Bd6 7.O-O

up to 5…d5 as line 143

6.b3: b3 prepares the bishop on b2 – White aims both bishops at your kingside. Stockfish: level (0).
6…Bd6: Stockfish had 6...c5 (0) just ahead; the gap is six hundredths.
7.O-O: Transposition to 6.O-O 6...Bd6 7.b3, where the course goes on. (transposition)

Line 145: 4.e3 Bb7 5.Bd3 d5 6.b3 Bd6 7.Bb2 O-O 8.O-O

up to 6…Bd6 as line 144

7.Bb2: The bishop goes to b2 onto the long diagonal – it watches e5 and c5.
7…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
8.O-O: White castles short; the bishop on d3 and the queen already eye your king. Stockfish: level (+0.05). (transposition)

Line 146: 4.e3 Bb7 5.Bd3 d5 6.cxd5 exd5 7.O-O Bd6 8.Nc3 O-O

up to 5…d5 as line 145

6.cxd5: White trades on d5 and fixes the structure.
6…exd5: Recapture with the pawn. Stockfish is clear: 6...exd5 (+0.02) against 6...Bb4 (+0.7).
7.O-O: White castles short; the bishop on d3 and the queen already eye your king.
7…Bd6: The bishop aims at h2. Stockfish chooses 7...Bd6 (+0.01) ahead of 7...a6 (+0.11).
8.Nc3: The knight goes to c3 and presses on d5 and e4.
8…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open. Stockfish: level (0). (transposition)

Line 147: 4.e3 Bb7 5.Bd3 d5 6.cxd5 exd5 7.O-O Bd6 8.b3 O-O 9.Ba3 c5 10.Nc3 Nbd7 11.Nb5 Bb8 12.Rc1 Qe7 13.Bf5 Ba6 14.Bd3 Bb7

up to 7…Bd6 as line 146

8.b3: b3 prepares the bishop on b2 – White aims both bishops at your kingside.
8…O-O: Stockfish would have chosen 8...Qe7 (-0.07) here; 8...O-O gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
9.Ba3: The bishop goes to a3 and offers to trade your good bishop.
9…c5: 9...c5 avoids the trade and attacks the pawn on d4.
10.Nc3: The knight goes to c3 and presses on d5 and e4.
10…Nbd7: The knight goes to d7 and supports e5 or c5 – your two freeing moves.
11.Nb5: The knight jumps to b5 and attacks your bishop on d6.
11…Bb8: The bishop retreats to b8 and stays on the diagonal against h2.
12.Rc1: The rook goes to c1 against your pawn on c5.
12…Qe7: The queen goes to e7 and connects the rooks; she covers c5 and e5.
13.Bf5: The bishop attacks your knight on d7.
13…Ba6: The bishop attacks the knight on b5 and asks White questions.
14.Bd3: The bishop retreats to d3 and covers the knight on b5.
14…Bb7: The bishop returns to b7 and covers d5. Stockfish: level (+0.14). (transposition)

Line 148: 4.e3 Bb7 5.Bd3 d5 6.cxd5 exd5 7.Nc3 Bd6 8.O-O

up to 6…exd5 as line 147

7.Nc3: The knight goes to c3 and presses on d5 and e4.
7…Bd6: The bishop goes to d6 and eyes h2 – in the quiet set-up with e3 your most active square.
8.O-O: White castles short; the bishop on d3 and the queen already eye your king. Stockfish: level (0). (transposition)

Line 149: 4.e3 Bb7 5.Bd3 d5 6.cxd5 exd5 7.b3 Bb4 8.Nbd2 Nbd7 9.Bb2 Qe7 10.Rc1 Bd6 11.O-O O-O 12.Nh4 g6 13.Rc2 a5 14.Nhf3 a4 15.bxa4 Ba6

up to 6…exd5 as line 148

7.b3: b3 prepares the bishop on b2 – White aims both bishops at your kingside.
7…Bb4: A move of Stockfish: with check the bishop disturbs White's development. 7...Bb4 (-0.08) is ahead of 7...Bd6 (+0.02).
8.Nbd2: The knight goes to d2 and covers c4 and e4.
8…Nbd7: The knight goes to d7 and supports e5 or c5 – your two freeing moves.
9.Bb2: The bishop goes to b2 onto the long diagonal – it watches e5 and c5.
9…Qe7: The queen goes to e7 and connects the rooks; she covers c5 and e5.
10.Rc1: The rook goes to c1 onto the c-file – it will open after c5 or cxd5.
10…Bd6: The bishop goes to d6 and eyes h2 – in the quiet set-up with e3 your most active square.
11.O-O: White castles short; the bishop on d3 and the queen already eye your king.
11…O-O: You castle short – your king is safe, and the rook on f8 can go to c8 or e8, where the files will open.
12.Nh4: The knight goes to h4 and on to f5.
12…g6: 12...g6 takes f5 away from the knight.
13.Rc2: The rook goes to c2 and wants to double the rooks.
13…a5: 13...a5 gains space on the queenside and takes b4 from White.
14.Nhf3: The knight returns to f3 and covers e5.
14…a4: 14...a4 attacks the pawn on b3 and wants to open the a-file.
15.bxa4: White takes on a4 – a pawn up, but the a-pawns are weak.
15…Ba6: The bishop attacks the bishop on d3 and offers a trade. Stockfish: level (+0.02).

Line 150: 4.e3 Bb7 5.Bd3 d5 6.Nc3 Bd6 7.O-O

up to 5…d5 as line 149

6.Nc3: The knight goes to c3 and presses on d5 and e4.
6…Bd6: The bishop goes to d6 and eyes h2 – in the quiet set-up with e3 your most active square.
7.O-O: White castles short; the bishop on d3 and the queen already eye your king. Stockfish: level (+0.02). (transposition)

Line 151: 4.e3 Bb7 5.Nc3 d5 6.cxd5 exd5 7.Bb5 c6 8.Bd3 Nbd7 9.O-O Be7 10.b3 O-O 11.Bb2 Bd6 12.Qc2 Re8 13.Rfe1 Rc8 14.Rad1 h6 15.Rc1 a6

up to 4…Bb7 as line 150

5.Nc3: The knight goes to c3 and presses on d5 and e4.
5…d5: You occupy the centre. Stockfish chooses 5...d5 (+0.07) clearly ahead of 5...Be7 (+0.19).
6.cxd5: White trades on d5 and fixes the structure.
6…exd5: Recapture with the pawn. Stockfish is sure: 6...exd5 (+0.11) against 6...Nxd5 (+0.46).
7.Bb5: The bishop gives check on b5 and disturbs your development.
7…c6: The bishop has to move. Stockfish is clear: 7...c6 (+0.01) against 7...Nbd7 (+0.46).
8.Bd3: The bishop retreats to d3 and eyes h7.
8…Nbd7: The knight goes to d7 and supports e5 or c5 – your two freeing moves.
9.O-O: White castles short; the bishop on d3 and the queen already eye your king.
9…Be7: Stockfish would have chosen 9...Bd6 (+0.08) here; 9...Be7 gives away about a tenth of a pawn – still within the tolerance of the course. The course follows the players' games here.
10.b3: b3 prepares the bishop on b2 – White aims both bishops at your kingside.
10…O-O: Stockfish would have chosen 10...Bd6 (0) here; 10...O-O gives away about two tenths of a pawn – still within the tolerance of the course. The course follows the players' games here.
11.Bb2: The bishop goes to b2 onto the long diagonal – it watches e5 and c5.
11…Bd6: The bishop goes to d6 and eyes h2 – in the quiet set-up with e3 your most active square.
12.Qc2: The queen goes to c2 and eyes h7 with the bishop on d3 – she also covers e4.
12…Re8: The rook goes to the half-open e-file against e3.
13.Rfe1: The rook goes to e1 and prepares e4.
13…Rc8: The rook goes to c8 and prepares c5.
14.Rad1: The rook goes to d1 and supports the pawn on d4.
14…h6: 14...h6 gives your king an escape square and takes g5 from White's bishop.
15.Rc1: The rook goes to c1 onto the c-file against c5.
15…a6: 15...a6 takes b5 from the knight on c3. Stockfish: level (0).

Line 152: 4.e3 Bb7 5.Nc3 d5 6.cxd5 exd5 7.Bd3

up to 6…exd5 as line 151

7.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling. Stockfish: level (0). (transposition)

Line 153: 4.e3 Bb7 5.Nc3 d5 6.Bd3

up to 5…d5 as line 152

6.Bd3: The bishop goes to d3 and eyes h7 – it prepares castling. Stockfish: level (+0.04). (transposition)