The Bogo-Indian Defense for Black – the whole course to read – Learning studio

Starting position after 1.d4 Nf6 2.c4 e6 3.Nf3 Bb4 4.Bd2 Qe7

The Bogo-Indian is the slim road against 3.Nf3: with 3...Bb4 Black gives check, and after 4.Bd2 the Nimzowitsch Variation 4...Qe7 protects the bishop. The queen keeps the square e5 in view and leaves you the choice of trading on d2. Against the main road 5.g3 the course plays 5...Nc6: the knight attacks d4 and prepares e5. After 6.Bg2 you trade with 6...Bxd2 and put your pawns on the dark squares with d6 and e5; after 6.Nc3 you take with 6...Bxc3 and jump with 7...Ne4 against the bishop on c3. Stockfish sees White slightly ahead in all lines, by two to four tenths – a normal value for Black in a solid opening. The course rests on 2744 games. White's other roads are 5.Nc3 and 5.e3.

The ideas

After the bishop trade the pawns belong on the dark squares: d6 and e5 replace the missing bishop.
If White pushes past with d5, the knight on c6 retreats – via b8 to a6 and c5, or via d8 to f7.
With the centre closed, Black plays on the kingside with f5, White on the queenside with c5 and b4.
The pawn on a5 secures the square c5 for the knight and slows down b4.
When White opens with c5 and cxd6, always recapture with the c-pawn – the queen move to d6 costs material in several lines.

To the course with board, lines and training →

Chapter 1: 5.g3

Line 1: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Rc1 O-O 9.Bg2 d6 10.d5 Nd8 11.dxe6 Nxe6 12.O-O Nxc3 13.Rxc3 Bd7 14.Re1 Bc6 15.e4 Rfe8

5.g3: White's main road, in eight games out of ten: the bishop is heading for g2. Stockfish sees the three moves 5.e3 (+0.28), 5.g3 (+0.27) and 5.a3 (+0.19) as practically equal.
5…Nc6: The plan of the Nimzowitsch Variation: the knight attacks d4 and prepares e5. Stockfish itself prefers to trade first with 5...Bxd2 (+0.24), then would come 5...O-O (+0.34); 5...Nc6 gives away a good two tenths. The course teaches it because the players choose it in seven games out of ten – and Stockfish's line 5...Bxd2 6.Qxd2 Nc6 also brings the knight to c6 one move later.
6.Nc3: Stockfish's first choice (+0.45, ahead of 6.e3 at +0.35): White develops and lets you trade on c3.
6…Bxc3: You give the bishop for the knight and go on at once with Ne4. Stockfish sees 6...d5 (+0.4) and 6...O-O (+0.41) just ahead; the gap to the course's move is six hundredths. The players choose the trade in more than half of the games because it leads to a clear plan.
7.Bxc3: White recaptures with the bishop and has the bishop pair – in return you get the square e4.
7…Ne4: The knight attacks the bishop on c3. Stockfish chooses 7...Ne4 (+0.47) ahead of 7...O-O (+0.57): Black wants to break up White's bishop pair.
8.Rc1: White keeps the bishop. Stockfish rates 8.Rc1 (+0.48) clearly ahead of 8.Qb3 (+0.21) and 8.Qc2 (+0.18) – after those two queen moves Black trades with 8...Nxc3 and offers the queen trade with Qb4.
8…O-O: The king first. Stockfish sees 8...O-O (+0.38) and 8...f5 (+0.39) as equally good.
9.Bg2: The bishop goes to g2 onto the long diagonal against b7 and e4.
9…d6: The typical pawn structure: d6 and soon e5. Stockfish chooses 9...d6 (+0.39) just ahead of 9...f5 (+0.41).
10.d5: White chases the knight from c6. For Stockfish the best move (+0.36), ahead of 10.O-O (+0.24) and 10.a3 (+0.14).
10…Nd8: The knight goes to d8, from where it can recapture on e6 or play via f7. At first sight Stockfish had 10...Nb8 (+0.43) just ahead of 10...Nd8 (+0.47); after the move it rates the position at +0.36 – the two retreats are practically equal.
11.dxe6: White releases the tension – for Stockfish a move that gives away almost three tenths: 11.Nd2 (+0.36) and 11.O-O (+0.34) were better, 11.dxe6 only +0.1.
11…Nxe6: Recapture with the knight: it stands well on e6 and eyes d4 and c5. Stockfish chooses 11...Nxe6 (+0.07) clearly ahead of 11...fxe6 (+0.22).
12.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal.
12…Nxc3: You trade off the bishop on c3 that was aiming at your kingside. Stockfish had 12...Bd7 (+0.14) and 12...Re8 (+0.2) ahead; after 12...Nxc3 it stays at +0.14 – equal.
13.Rxc3: The rook recaptures on c3 and stands actively on the third rank – it covers the c-file.
13…Bd7: The bishop comes into play. Stockfish chooses 13...Bd7 (+0.12) ahead of 13...Qf6 (+0.19); its line shows the rooks on e8 and d8.
14.Re1: The rook goes to e1 and prepares e4. Stockfish: level (+0.13).
14…Bc6: The bishop opposes the bishop on g2 on the long diagonal. Stockfish would first have played 14...Rfe8 (+0.13) and Bc6 a move later; the difference is three hundredths.
15.e4: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
15…Rfe8: The line ends with Black's 15th move. Stockfish rates the position at +0.22 – almost level.

Line 2: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Rc1 O-O 9.Bg2 d6 10.d5 Nd8 11.dxe6 Nxe6 12.Bb4 c5 13.Bc3 Rb8 14.O-O Nxc3 15.Rxc3 Rd8

up to 11…Nxe6 as line 1

12.Bb4: The bishop dodges the knight but costs a good tenth against 12.O-O – Black is equal.
12…c5: A move of Stockfish: with tempo against the bishop. After 13.Ba3 f5 the knight on e4 stands firmly and Black has play on the kingside.
13.Bc3: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
13…Rb8: The rook goes to b8 and prepares b5.
14.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal.
14…Nxc3: You trade on c3 and take White's bishop of the long diagonal.
15.Rxc3: The rook recaptures on c3 and stands actively on the third rank – it covers the c-file. Stockfish: level (-0.07).
15…Rd8: The line ends with Black's 15th move. Stockfish rates the position at 0 – almost level.

Line 3: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Rc1 O-O 9.Bg2 d6 10.d5 Nd8 11.O-O e5 12.Nd2 Nxc3 13.Rxc3 f5 14.c5 Nf7 15.cxd6 cxd6 16.Qb3 b6 17.Rfc1 Bd7

up to 10…Nd8 as line 2

11.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal.
11…e5: You close the centre. Stockfish sees 11...f5 (+0.32) and 11...e5 (+0.33) as equal, only one hundredth apart. With the centre closed the kingside belongs to you: the knight on d8 comes via f7, the f-pawn advances.
12.Nd2: White attacks the knight on e4. Stockfish would have played 12.c5 (+0.46); 12.Nd2 gives away almost three tenths.
12…Nxc3: Take on c3, not on d2: 12...Nxc3 (+0.06) against 12...Nxd2 (+0.87) – almost a pawn of difference, because after the recapture on d2 White's bishop survives.
13.Rxc3: The rook recaptures on c3 and stands actively on the third rank – it covers the c-file.
13…f5: The typical push against the kingside. Stockfish prefers 13...b6 (+0.14) here; 13...f5 (+0.37) is the second choice. The course teaches the plan of the players, who choose it in two games out of three – it gives away about two tenths.
14.c5: White opens the c-file and attacks d6.
14…Nf7: The knight guards d6. Stockfish chooses 14...Nf7 (+0.34) ahead of 14...dxc5 (+0.38).
15.cxd6: White takes on d6 and opens the c-file for his rook.
15…cxd6: Recapture with the pawn! Stockfish is clear: 15...cxd6 (+0.3) against 15...Nxd6 (+1.18). The pawn on d6 holds e5 and the square c5.
16.Qb3: The queen goes to b3 and eyes b7 and f7.
16…b6: The pawn leaves the queen's attack and guards c5. Stockfish chooses 16...b6 (+0.34) ahead of 16...g6 (+0.52).
17.Rfc1: The rook goes to c1 and doubles on the c-file. Stockfish sees White slightly ahead (+0.33).
17…Bd7: A move of Stockfish: the bishop develops, then the rook comes to c8 against White's rooks. 17...Bd7 (+0.39) is ahead of 17...g6 (+0.6).

Line 4: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Rc1 O-O 9.Bg2 d6 10.d5 Nd8 11.O-O e5 12.Nd2 Nxc3 13.Rxc3 f5 14.c5 Nf7 15.Qb3 b6

up to 14…Nf7 as line 3

15.Qb3: The queen goes to b3 and eyes b7 and f7. Stockfish sees White slightly ahead (+0.36).
15…b6: A move of Stockfish: as in the line with 15.cxd6, 15...b6 covers the pawn on b7 and the square c5. Stockfish rates it at +0.32 ahead of 15...g6 (+0.56).

Line 5: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Rc1 O-O 9.Bg2 d6 10.d5 Nd8 11.O-O e5 12.c5 f5 13.cxd6 cxd6 14.Qd3 Nf7 15.Nd2 Nf6

up to 11…e5 as line 4

12.c5: Stockfish's own choice (+0.46): White opens the c-file at once.
12…f5: A move of Stockfish: counterplay on the kingside instead of defence. 12...f5 (+0.37) is ahead of 12...Bd7 (+0.48).
13.cxd6: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
13…cxd6: Watch out: only 13...cxd6 (+0.45) holds here – 13...Nxd6 (+5.21) would be a serious mistake.
14.Qd3: The queen goes to d3 and attacks your knight on e4.
14…Nf7: The knight goes to f7 and covers d6, e5 and g5 – in the closed centre it stands well there.
15.Nd2: The knight goes to d2 and attacks your knight on e4. Stockfish: level (+0.27).
15…Nf6: The line ends with Black's 15th move. Stockfish rates the position at +0.28 – almost level.

Line 6: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Rc1 O-O 9.Bg2 d6 10.d5 Nd8 11.Nd2 Nxc3 12.Rxc3 e5 13.c5 f5 14.cxd6 cxd6 15.O-O Nf7

up to 10…Nd8 as line 5

11.Nd2: Stockfish's first choice (+0.36): White attacks the knight on e4.
11…Nxc3: You trade on c3. Stockfish chooses 11...Nxc3 (+0.35) just ahead of 11...exd5 (+0.38).
12.Rxc3: The rook recaptures on c3 and stands actively on the third rank – it covers the c-file.
12…e5: The centre is closed. Stockfish would first have played 12...f5 (+0.32); 12...e5 (+0.45) gives away a good tenth. The players choose e5 in seven games out of ten.
13.c5: c5 attacks your pawn on d6 – White wants to open lines on the queenside.
13…f5: Counterattack instead of defending d6. Stockfish chooses 13...f5 (+0.33) ahead of 13...dxc5 (+0.46).
14.cxd6: White takes on d6 and opens the c-file for his rook.
14…cxd6: Watch out: recapture only with the pawn. 14...cxd6 (+0.4) against 14...Qxd6 (+1.15) – after the queen move 15.Nc4 comes with tempo.
15.O-O: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
15…Nf7: The knight goes to f7 and covers d6, e5 and g5 – in the closed centre it stands well there. Stockfish sees White slightly ahead (+0.39). (transposition)

Line 7: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Rc1 O-O 9.Bg2 d6 10.d5 Nd8 11.Bb4 a5 12.Ba3 e5 13.Nd2 Nc5 14.O-O b6 15.b3 f5

up to 10…Nd8 as line 6

11.Bb4: White saves the bishop, but Stockfish sees equality afterwards: 11.Bb4 gives away more than three tenths against 11.Nd2.
11…a5: With tempo against the bishop. Stockfish sees 11...e5 (0) and 11...a5 (0) as equally good.
12.Ba3: The bishop goes to a3 and keeps the diagonal against d6 and f8.
12…e5: Now you close the centre. Stockfish chooses 12...e5 (0) clearly ahead of 12...f5 (+0.31); its line shows the knight on e4 on its way to c5.
13.Nd2: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
13…Nc5: The knight goes to c5 and stands strongly there – it attacks e4 and b3.
14.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal.
14…b6: 14...b6 supports the knight on c5, which stands firmly there and attacks e4 and b3.
15.b3: 15.b3 takes b3 and a4 from your knight. Stockfish: level (-0.09).
15…f5: The line ends with Black's 15th move. Stockfish rates the position at -0.1 – almost level.

Line 8: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Rc1 O-O 9.Bg2 d6 10.O-O Nxc3 11.Rxc3 e5 12.d5 Nb8 13.Nd2 a5 14.c5 Na6 15.cxd6 cxd6 16.Nc4 Qd8

up to 9…d6 as line 7

10.O-O: White castles instead of chasing the knight with 10.d5 – for Stockfish almost two tenths weaker.
10…Nxc3: You trade the bishop on c3. Stockfish would first have played 10...e5 (+0.18); 10...Nxc3 (+0.32) is the second choice. The players choose the trade in seven games out of ten; the difference is a good tenth.
11.Rxc3: The rook recaptures on c3 and stands actively on the third rank – it covers the c-file.
11…e5: The plan: e5 against d4. Stockfish chooses 11...e5 (+0.25) clearly ahead of 11...Bd7 (+0.52).
12.d5: d5 gains space and drives your knight from c6 – White closes the centre.
12…Nb8: The knight retreats to reach c5 via d7 or a6. Stockfish chooses 12...Nb8 (+0.21) ahead of 12...Nd8 (+0.34).
13.Nd2: The knight goes to d2 and prepares c5.
13…a5: The pawn secures the square c5 and slows down b4. Stockfish had 13...Nd7 (+0.16) just ahead; 13...a5 (+0.21) is five hundredths behind.
14.c5: c5 attacks your pawn on d6 – White wants to open lines on the queenside.
14…Na6: The knight is on its way to c5. Stockfish chooses 14...Na6 (+0.14) ahead of 14...Nd7 (+0.22).
15.cxd6: White takes on d6 and opens the c-file for his rook.
15…cxd6: A trap for yourself: take with the pawn! 15...cxd6 (+0.32) against 15...Qxd6 (+3.49) – after 16.Nc4 the queen is attacked, and Stockfish sees White clearly winning.
16.Nc4: The knight goes to c4 and eyes b6 and d6. Stockfish: level (+0.20).
16…Qd8: The queen steps aside. Stockfish chooses 16...Qd8 (+0.2) far ahead of 16...Nc5 (+1.25).

Line 9: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Rc1 O-O 9.Bg2 d6 10.O-O Nxc3 11.Rxc3 e5 12.d5 Nb8 13.b4 a5 14.Ra3 b6 15.Nd2 Nd7

up to 12…Nb8 as line 8

13.b4: 13.b4 gains space on the queenside and prepares c5.
13…a5: You attack the pawn on b4 at once. Stockfish would have played 13...Nd7 (0); 13...a5 (+0.04) is only four hundredths behind.
14.Ra3: The rook goes to a3 and covers the third rank. Stockfish: level (+0.03).
14…b6: A move of Stockfish: the pawn holds the queenside together. Stockfish sees 14...Bg4 (+0.11) and 14...b6 (+0.12) as equal.
15.Nd2: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
15…Nd7: The line ends with Black's 15th move. Stockfish rates the position at +0.06 – almost level.

Line 10: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Rc1 O-O 9.Bg2 d6 10.O-O Nxc3 11.Rxc3 e5 12.d5 Nb8 13.e4 Bg4 14.Qc2 Bxf3 15.Rxf3 a5

up to 12…Nb8 as line 9

13.e4: White extends the centre, but that gives away almost a quarter of a pawn – Black is slightly better afterwards.
13…Bg4: A move of Stockfish: the bishop pins the knight on f3. 13...Bg4 (-0.11) is ahead of 13...a5 (+0.1).
14.Qc2: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
14…Bxf3: You trade on f3 and take away a defender of d4 and e5.
15.Rxf3: The rook recaptures on f3 and stands on the f-file – level.
15…a5: The line ends with Black's 15th move. Stockfish rates the position at -0.04 – almost level.

Line 11: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Rc1 O-O 9.Bg2 d6 10.O-O Nxc3 11.Rxc3 e5 12.d5 Nb8 13.Qc2 a5 14.c5 Na6 15.cxd6 cxd6

up to 12…Nb8 as line 10

13.Qc2: For Stockfish an inaccurate move: it gives away more than a quarter of a pawn against 13.Nd2.
13…a5: Again the pawn to a5 for the square c5. Stockfish chooses 13...a5 (-0.09) ahead of 13...b6 (+0.01).
14.c5: c5 attacks your pawn on d6 – White wants to open lines on the queenside.
14…Na6: The knight wants to go to c5. Stockfish is sure: 14...Na6 (-0.1) against 14...Nd7 (+0.26).
15.cxd6: White takes on d6 and opens the c-file for his rook. Stockfish: level (-0.03).
15…cxd6: Recapture with the pawn, not with the queen: 15...cxd6 (-0.03) against 15...Qxd6 (+2.32).

Line 12: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Qc2 Nxc3 9.Qxc3 O-O 10.Bg2 d6 11.O-O e5 12.d5 Nd8 13.e4 c5 14.Nd2 g6 15.f4 f6

up to 7…Ne4 as line 11

8.Qc2: White protects the bishop with the queen. For Stockfish less accurate than 8.Rc1 – about three tenths weaker.
8…Nxc3: You take the bishop pair. Stockfish chooses 8...Nxc3 (+0.18) clearly ahead of 8...d5 (+0.57).
9.Qxc3: The queen recaptures on c3 and stands on the long diagonal against g7.
9…O-O: You castle. Stockfish would have offered the queen trade with 9...Qb4 (+0.13); 9...O-O (+0.27) is the second choice. The players keep the queens on in more than half of the games.
10.Bg2: The bishop goes to g2 onto the long diagonal against b7 and e4.
10…d6: Again d6 and e5. Stockfish chooses 10...d6 (+0.31) ahead of 10...a5 (+0.37).
11.O-O: White castles – Stockfish would have chased the knight with 11.d5 (+0.44).
11…e5: You attack d4. Stockfish chooses 11...e5 (+0.11) clearly ahead of 11...Qf6 (+0.46).
12.d5: d5 gains space and drives your knight from c6 – White closes the centre.
12…Nd8: The knight goes via d8 to f7. Stockfish would have played 12...Nb8 (+0.2); 12...Nd8 (+0.34) gives away about a tenth.
13.e4: e4 builds the centre and takes d5 from your knight.
13…c5: You close the queenside. Stockfish had 13...f6 (+0.19) just ahead; the gap is three hundredths.
14.Nd2: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
14…g6: 14...g6 prepares f5 and covers h5.
15.f4: 15.f4 gains space on the kingside and attacks e5. Stockfish: level (+0.16).
15…f6: The line ends with Black's 15th move. Stockfish rates the position at +0.14 – almost level.

Line 13: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Qc2 Nxc3 9.Qxc3 O-O 10.Bg2 d6 11.O-O e5 12.d5 Nd8 13.c5 f5 14.Rac1 Nf7 15.cxd6 cxd6

up to 12…Nd8 as line 12

13.c5: Stockfish's first choice (+0.29): White opens the c-file.
13…f5: Counterplay on the kingside. Stockfish chooses 13...f5 (+0.29) clearly ahead of 13...b6 (+0.48).
14.Rac1: The rook goes to c1 and prepares cxd6. Stockfish sees White slightly ahead (+0.38).
14…Nf7: The knight guards d6. Stockfish would first have played 14...b6 (+0.34); 14...Nf7 gives away only four hundredths.
15.cxd6: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
15…cxd6: The line ends with Black's 15th move. Stockfish rates the position at +0.58 – slightly better for White.

Line 14: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Qc2 Nxc3 9.Qxc3 O-O 10.Bg2 d6 11.O-O e5 12.d5 Nd8 13.c5 f5 14.Rac1 b6 15.cxd6 cxd6

up to 14.Rac1 as line 13

14…b6: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
15.cxd6: White takes on d6 and opens the c-file for his rook. Stockfish sees White slightly ahead (+0.41).
15…cxd6: The line ends with Black's 15th move. Stockfish rates the position at +0.31 – slightly better for White.

Line 15: 5.g3 Nc6 6.Nc3 Bxc3 7.Bxc3 Ne4 8.Qc2 Nxc3 9.Qxc3 O-O 10.Bg2 d6 11.d5 Nd8 12.O-O e5

up to 10…d6 as line 14

11.d5: Stockfish's choice (+0.44): the knight on c6 must move.
11…Nd8: Stockfish chooses 11...Nd8 (+0.33) ahead of 11...Nb8 (+0.4).
12.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal. Stockfish sees White slightly ahead (+0.39).
12…e5: Transposition: the position is the same as after 11.O-O e5 12.d5 Nd8, where the course goes on. Stockfish sees 12...f5 (+0.39) and 12...e5 (+0.41) as almost equal. (transposition)

Line 16: 5.g3 Nc6 6.Bg2 Bxd2 7.Nbxd2 d6 8.O-O a5 9.e4 e5 10.d5 Nb8 11.Ne1 O-O 12.Nd3 Na6 13.f4 Nd7 14.f5 Nac5 15.Qe2 Qg5

up to 5…Nc6 as line 15

6.Bg2: White leaves the bishop on d2 – for Stockfish a quarter of a pawn weaker than 6.Nc3.
6…Bxd2: Now you trade. Stockfish is clear: 6...Bxd2 (+0.32) against 6...O-O (+0.57).
7.Nbxd2: Stockfish's choice (+0.17). Not 7.Nfxd2 (-0.96): then the pawn on d4 falls after 7...Nxd4.
7…d6: The plan d6 and e5: your pawns stand on the dark squares where your bishop is missing. Stockfish chooses 7...d6 (+0.29) ahead of 7...O-O (+0.36).
8.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal.
8…a5: The pawn secures the square b4 and prepares the knight's route via a6. Stockfish had 8...e5 (+0.14) and 8...O-O (+0.15) ahead; the course's move (8...a5, +0.23) gives away only about a tenth and is the players' move in every second game.
9.e4: e4 builds the centre and takes d5 from your knight.
9…e5: Now e5. Stockfish chooses 9...e5 (+0.25) ahead of 9...O-O (+0.34).
10.d5: d5 gains space and drives your knight from c6 – White closes the centre.
10…Nb8: The knight retreats and comes to c5 via d7 or a6. Stockfish chooses 10...Nb8 (+0.2) ahead of 10...Nd8 (+0.25).
11.Ne1: The most common move: the knight wants to go to d3 and support f4 from there. Stockfish would have played 11.Qa4 (+0.24); 11.Ne1 gives away almost two tenths.
11…O-O: The king first. Stockfish had 11...Nbd7 (+0.06) and 11...h5 (+0.07) just ahead; the gap is six hundredths.
12.Nd3: The knight reaches d3 and supports f4 and c5.
12…Na6: The knight comes into play via a6 and aims at c5 and b4. Stockfish had 12...b6 (+0.06) ahead, then 12...Nbd7 (+0.13); 12...Na6 gives away just under a tenth and is the move of eight out of ten players.
13.f4: White attacks the centre with the f-pawn.
13…Nd7: The knight heads for c5. Stockfish saw 13...b6 (+0.13) and 13...Bd7 (+0.15) just ahead; the difference is six hundredths.
14.f5: 14.f5 gains space on the kingside and closes your bishop's diagonal.
14…Nac5: A move of Stockfish: the knight attacks the knight on d3. 14...Nac5 (+0.09) is ahead of 14...Nf6 (+0.12).
15.Qe2: The queen goes to e2 and covers c4 and e4. Stockfish: level (+0.13).
15…Qg5: The line ends with Black's 15th move. Stockfish rates the position at +0.1 – almost level.

Line 17: 5.g3 Nc6 6.Bg2 Bxd2 7.Nbxd2 d6 8.O-O a5 9.e4 e5 10.d5 Nb8 11.Ne1 O-O 12.Nd3 Na6 13.a3 c6 14.dxc6 bxc6 15.b4 h5

up to 12…Na6 as line 16

13.a3: Stockfish's choice (+0.15): White takes the square b4 from the knight.
13…c6: You attack the centre with the c-pawn. Stockfish would have chosen 13...Bg4 (0); 13...c6 (+0.19) is the second choice.
14.dxc6: White takes on c6 and opens the b-file.
14…bxc6: Recapture with the b-pawn, towards the centre. Stockfish is sure: 14...bxc6 (+0.03) against 14...Bg4 (+0.33).
15.b4: 15.b4 gains space on the queenside and attacks your knight on a6.
15…h5: A move of Stockfish: the h-pawn advances to loosen White's kingside.

Line 18: 5.g3 Nc6 6.Bg2 Bxd2 7.Nbxd2 d6 8.O-O a5 9.e4 e5 10.d5 Nb8 11.Ne1 O-O 12.Nd3 Na6 13.b3 c6 14.a3 Bd7 15.Re1 h6

up to 12…Na6 as line 17

13.b3: 13.b3 supports the pawn on c4 – White wants to open the queenside with b4 and c5.
13…c6: Again the lever c6. Stockfish had 13...b6 (+0.1) just ahead; the gap is two hundredths.
14.a3: 14.a3 prepares b4 – White plays on the queenside, you on the kingside.
14…Bd7: A move of Stockfish: the bishop develops. 14...cxd5 (+0.04) and 14...Bd7 (+0.05) are equal.
15.Re1: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
15…h6: The line ends with Black's 15th move. Stockfish rates the position at +0.09 – almost level.

Line 19: 5.g3 Nc6 6.Bg2 Bxd2 7.Nbxd2 d6 8.O-O a5 9.e4 e5 10.d5 Nb8 11.Ne1 O-O 12.Nd3 Na6 13.Qc2 c6 14.Qc3 cxd5 15.cxd5 Bd7

up to 12…Na6 as line 18

13.Qc2: The queen goes to c2 and covers c4 and e4.
13…c6: The lever against d5. Stockfish had 13...Bd7 (+0.1) ahead; 13...c6 gives away about a tenth.
14.Qc3: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
14…cxd5: You take on d5 and open the c-file.
15.cxd5: White recaptures – the c-file is open. Stockfish: level (+0.21).
15…Bd7: The line ends with Black's 15th move. Stockfish rates the position at +0.23 – almost level.

Line 20: 5.g3 Nc6 6.Bg2 Bxd2 7.Nbxd2 d6 8.O-O a5 9.e4 e5 10.d5 Nb8 11.Ne1 O-O 12.b3 Na6 13.a3 Bg4 14.f3 Bd7 15.Nd3 c6

up to 11…O-O as line 19

12.b3: 12.b3 supports the pawn on c4 – White wants to open the queenside with b4 and c5.
12…Na6: The knight on its way to c5. Stockfish sees 12...Bg4 (0) and 12...Na6 (+0.01) as equal.
13.a3: 13.a3 takes b4 from your knight.
13…Bg4: The bishop attacks and forces White to play f3. Stockfish chooses 13...Bg4 (+0.04) ahead of 13...c6 (+0.12).
14.f3: 14.f3 attacks your bishop on g4 and covers e4.
14…Bd7: Back to d7; the pawn on f3 takes a square from the knight on e1. Stockfish chooses 14...Bd7 (0) ahead of 14...Bc8 (+0.15).
15.Nd3: The knight reaches d3 and supports f4 and c5. Stockfish: level (0).
15…c6: The lever against d5. Stockfish chooses 15...c6 (0) ahead of 15...h6 (+0.17).

Line 21: 5.g3 Nc6 6.Bg2 Bxd2 7.Nbxd2 d6 8.O-O a5 9.e4 e5 10.d5 Nb8 11.c5 O-O 12.cxd6 cxd6 13.Ne1 h5 14.h3 Bd7 15.Qb3 Na6

up to 10…Nb8 as line 20

11.c5: White opens the c-file but gives away almost a quarter of a pawn against 11.Qa4.
11…O-O: Stockfish sees 11...Nbd7 (0) and 11...O-O (0) as equally good.
12.cxd6: White takes on d6 and opens the c-file for his rook.
12…cxd6: Watch out: recapture with the pawn! 12...cxd6 (+0.06) against 12...Qxd6 (+2.7) – after 13.Nc4 the knight comes with tempo and White wins the pawn on e5.
13.Ne1: The knight goes to e1 and on to d3.
13…h5: A move of Stockfish: the h-pawn loosens White's kingside. Stockfish had 13...Nbd7 (-0.12) just ahead; 13...h5 (-0.04) is the second choice – Black is slightly better.
14.h3: 14.h3 takes g4 from your knight and bishop.
14…Bd7: The bishop goes to d7 and covers the queenside.
15.Qb3: The queen goes to b3 and attacks the pawn on b7 – White uses the open c-file.
15…Na6: The line ends with Black's 15th move. Stockfish rates the position at -0.01 – almost level.

Line 22: 5.g3 Nc6 6.Bg2 Bxd2 7.Nbxd2 d6 8.O-O a5 9.e4 e5 10.d5 Nb8 11.b3 O-O 12.a3 Na6 13.Qe2 c6 14.Rfc1 Bd7 15.Ne1 Rfc8

up to 10…Nb8 as line 21

11.b3: 11.b3 supports the pawn on c4 – White wants to open the queenside with b4 and c5.
11…O-O: Stockfish chooses 11...O-O (+0.12) just ahead of 11...Na6 (+0.13).
12.a3: 12.a3 prepares b4 – White plays on the queenside, you on the kingside.
12…Na6: The knight on its way to c5. Stockfish chooses 12...Na6 (+0.15) ahead of 12...Bd7 (+0.25).
13.Qe2: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
13…c6: 13...c6 opens the c-file against c4 and attacks d5.
14.Rfc1: The rook goes to c1 onto the c-file, which is just opening.
14…Bd7: The bishop goes to d7 and connects the rooks.
15.Ne1: The knight goes to e1 and on to d3 – it prepares f4. Stockfish: level (0).
15…Rfc8: The line ends with Black's 15th move. Stockfish rates the position at 0 – almost level.

Line 23: 5.g3 Nc6 6.Bg2 Bxd2 7.Nbxd2 d6 8.e4 e5 9.d5 Nb8 10.O-O a5

up to 7…d6 as line 22

8.e4: e4 builds the centre and takes d5 from your knight.
8…e5: The pawn against d4. Stockfish had 8...O-O (+0.13) ahead; 8...e5 gives away only five hundredths.
9.d5: d5 gains space and drives your knight from c6 – White closes the centre.
9…Nb8: Stockfish chooses 9...Nb8 (+0.29) ahead of 9...Nd8 (+0.34).
10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal. Stockfish: level (+0.14).
10…a5: Transposition to 8.O-O a5 9.e4 e5 10.d5 Nb8, where the course goes on. Stockfish chooses 10...a5 (+0.14) ahead of 10...O-O (+0.18). (transposition)

Line 24: 5.g3 Nc6 6.Bg2 Bxd2 7.Nbxd2 d6 8.e4 e5 9.d5 Nb8 10.b4 a5 11.a3 Bg4 12.O-O Nbd7 13.Qc2 Bxf3 14.Bxf3 O-O 15.Bg2 Rfb8

up to 9…Nb8 as line 23

10.b4: 10.b4 gains space on the queenside and prepares c5.
10…a5: You attack the pawn on b4 at once. Stockfish chooses 10...a5 (+0.15) ahead of 10...O-O (+0.17).
11.a3: 11.a3 supports b4 and prepares c5.
11…Bg4: A move of Stockfish: the bishop pins the knight on f3. 11...Bg4 (+0.11) is ahead of 11...O-O (+0.17).
12.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal.
12…Nbd7: The knight goes to d7 and covers c5 and e5.
13.Qc2: The queen goes to c2 and covers e4 against your pressure.
13…Bxf3: You trade on f3 and take away a defender of e5.
14.Bxf3: White recaptures with the bishop and has the bishop pair.
14…O-O: You castle – your king is safe, and the rook on f8 will later support f5.
15.Bg2: The bishop returns to g2 – level. Stockfish: level (0).
15…Rfb8: The line ends with Black's 15th move. Stockfish rates the position at +0.01 – almost level.

Line 25: 5.g3 Nc6 6.Bg2 Bxd2 7.Nbxd2 d6 8.Nf1 O-O 9.Ne3 e5 10.O-O Re8 11.Re1 h6 12.a3 a5 13.d5 Nb8 14.b4 Ng4 15.Nxg4 Bxg4

up to 7…d6 as line 24

8.Nf1: The knight goes to f1 and on to e3 – there it covers d5 and c4.
8…O-O: The knight wants to go to e3 and d5. Stockfish chooses 8...O-O (+0.1) clearly ahead of 8...e5 (+0.21).
9.Ne3: The knight reaches e3 and covers d5 and c4.
9…e5: The plan e5. Stockfish had 9...Re8 (+0.15) ahead; 9...e5 gives away just under a tenth.
10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal.
10…Re8: The rook supports e5. Stockfish chooses 10...Re8 (+0.15) ahead of 10...h6 (+0.24).
11.Re1: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
11…h6: 11...h6 gives the king air and takes g5 from the knight.
12.a3: 12.a3 prepares b4 – White plays on the queenside, you on the kingside.
12…a5: 12...a5 prevents b4 and keeps the queenside closed.
13.d5: d5 gains space and drives your knight from c6 – White closes the centre.
13…Nb8: The knight retreats to b8 and wants to reach d7.
14.b4: 14.b4 opens the queenside anyway and gives a pawn.
14…Ng4: The knight attacks the knight on e3 and wants to trade it.
15.Nxg4: White trades on g4 and simplifies – level.
15…Bxg4: The line ends with Black's 15th move. Stockfish rates the position at +0.1 – almost level.

Line 26: 5.g3 Nc6 6.Bg2 Bxd2 7.Qxd2 Ne4 8.Qc2 Qb4 9.Nc3 Nxc3 10.Qxc3 Qxc3 11.bxc3 d6 12.Nd2 Na5 13.f4 Rb8 14.Kf2 Ke7 15.Be4 b6

up to 6…Bxd2 as line 25

7.Qxd2: Recapture with the queen – for Stockfish the second choice (+0.06) behind 7.Nbxd2 (+0.17).
7…Ne4: With tempo against the queen. Stockfish chooses 7...Ne4 (+0.08) clearly ahead of 7...Qb4 (+0.45).
8.Qc2: The queen goes to c2 and attacks your knight on e4.
8…Qb4: Check! The queen also attacks c4. Stockfish is clear: 8...Qb4 (+0.13) against 8...d5 (+0.71).
9.Nc3: White blocks with the knight. Stockfish would have played 9.Kf1 (+0.16); 9.Nc3 (+0.07) is the second choice.
9…Nxc3: You trade. Stockfish chooses 9...Nxc3 (-0.03) clearly ahead of 9...Nf6 (+0.61).
10.Qxc3: The queen recaptures on c3 and offers a queen trade.
10…Qxc3: You go into the endgame, and White gets doubled pawns on c3 and c4. Stockfish chooses 10...Qxc3 (0) ahead of 10...d6 (+0.22).
11.bxc3: White recaptures with the pawn and has doubled pawns on the c-file.
11…d6: The pawn controls e5. Stockfish had 11...Na5 (0) against the pawn on c4 just ahead, then 11...Rb8 (+0.04); the gap is six hundredths.
12.Nd2: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
12…Na5: The knight goes to a5 and attacks the pawn on c4.
13.f4: 13.f4 gains space on the kingside and takes e5 from the knight.
13…Rb8: The rook goes to b8 and prepares b6.
14.Kf2: The king goes to f2 – in the endgame it belongs in the centre.
14…Ke7: The king goes to e7 and covers d6 – in the endgame it is an active piece.
15.Be4: The bishop goes to e4 – a level endgame. Stockfish: level (-0.04).
15…b6: The line ends with Black's 15th move. Stockfish rates the position at 0 – almost level.

Line 27: 5.g3 Nc6 6.Bg2 Bxd2 7.Qxd2 Ne4 8.Qc2 Qb4 9.Kf1 d5 10.e3 dxc4 11.Kg1 O-O 12.h3 Nd6 13.Kh2 f6 14.Nc3 Bd7 15.Nd2 Be8

up to 8…Qb4 as line 26

9.Kf1: Stockfish's choice (+0.16): the king steps out of check but loses the right to castle.
9…d5: The pawn protects the knight on e4. Stockfish chooses 9...d5 (+0.06) ahead of 9...f5 (+0.3).
10.e3: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
10…dxc4: You take on c4 and win a pawn.
11.Kg1: The king goes to g1 – White can no longer castle.
11…O-O: You castle – your king is safe, and the rook on f8 will later support f5.
12.h3: 12.h3 gives the king an escape square and takes g5 from the pieces.
12…Nd6: The knight goes to d6 and covers the extra pawn on c4.
13.Kh2: The king goes to h2 and connects the rooks.
13…f6: 13...f6 prepares e5 and covers g5.
14.Nc3: The knight goes to c3 and attacks c4.
14…Bd7: The bishop goes to d7 and connects the rooks.
15.Nd2: The knight goes to d2 and attacks c4. Stockfish: level (+0.07).
15…Be8: The line ends with Black's 15th move. Stockfish rates the position at +0.07 – almost level.

Line 28: 5.g3 Nc6 6.Bg2 Bxd2 7.Qxd2 Ne4 8.Qc2 Qb4 9.Nbd2 Nxd2 10.Qxd2 Qxc4 11.O-O Qb4 12.Qc2 d5 13.Rac1 O-O 14.a3 Qb6 15.Rfd1 h6

up to 8…Qb4 as line 27

9.Nbd2: A mistake that costs more than three tenths: after the trade on d2 the pawn on c4 falls.
9…Nxd2: Trade now! 9...Nxd2 (-0.24) against 9...d5 (+1.26).
10.Qxd2: The queen recaptures on d2 and offers a queen trade.
10…Qxc4: You take the pawn on c4. Stockfish chooses 10...Qxc4 (-0.27) clearly ahead of the queen trade 10...Qxd2 (+0.31).
11.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal.
11…Qb4: The queen retreats and offers the trade. Stockfish chooses 11...Qb4 (-0.22) ahead of 11...f6 (0).
12.Qc2: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
12…d5: 12...d5 supports c4 and builds a centre.
13.Rac1: The rook goes to c1 and attacks the pawn on c4.
13…O-O: You castle – your king is safe, and the rook on f8 will later support f5.
14.a3: 14.a3 attacks your queen and gains time.
14…Qb6: The queen goes to b6 and keeps hold of the pawn on c4.
15.Rfd1: The rook goes to d1 – you stand slightly better. Stockfish: level (-0.29).
15…h6: The line ends with Black's 15th move. Stockfish rates the position at -0.2 – almost level.

Chapter 2: 5.Nc3

Line 29: 5.Nc3 O-O 6.g3 d6 7.Bg2 e5 8.O-O Bxc3 9.Bxc3 e4 10.Ne1 d5 11.Nc2 Re8 12.Ne3 c6 13.Rc1 h6 14.Qd2 Na6 15.b3 h5

5.Nc3: White lets you trade on c3. Stockfish sees 5.Nc3 about a seventh of a pawn behind 5.e3.
5…O-O: The king first. Stockfish had 5...Bxc3 (+0.13) and 5...b6 (+0.14) ahead; 5...O-O gives away just under a tenth and keeps both plans open.
6.g3: 6.g3 prepares the fianchetto – the bishop is to work against b7 and e4.
6…d6: The familiar set-up with d6 and e5. Stockfish had 6...d5 (+0.18) ahead; the course's move stays at +0.18 – equal.
7.Bg2: The bishop goes to g2 onto the long diagonal against b7 and e4.
7…e5: Stockfish chooses 7...e5 (+0.21) ahead of 7...a5 (+0.27).
8.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal.
8…Bxc3: A move of Stockfish: after 9.Bxc3 e4 10.Ne1 the e-pawn gains space and the knight on f3 must retreat. 8...Bxc3 (-0.01) is clearly ahead of 8...Re8 (+0.22).
9.Bxc3: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
9…e4: 9...e4 attacks the knight on f3 and gains space.
10.Ne1: The knight goes to e1 and on to c2.
10…d5: Watch out: only 10...d5 (0) holds here – 10...e3 (+0.82) would be a serious mistake.
11.Nc2: The knight goes to c2 and on to e3.
11…Re8: The rook goes to e8 and covers the outpost on e4.
12.Ne3: The knight reaches e3 and presses on d5.
12…c6: 12...c6 supports the pawn on d5 against the knight on e3.
13.Rc1: The rook goes to c1 onto the c-file and prepares c5.
13…h6: 13...h6 gives the king an escape square and takes g5 from the pieces.
14.Qd2: The queen goes to d2 and connects the rooks.
14…Na6: The knight goes to a6 and on to c7.
15.b3: 15.b3 supports c4 and prepares f3 – level.
15…h5: The line ends with Black's 15th move. Stockfish rates the position at +0.05 – almost level.

Line 30: 5.Nc3 O-O 6.Qc2 d6 7.a3 Bxc3 8.Bxc3 Nbd7 9.e3 a5 10.Be2 b6 11.O-O Bb7 12.b4 axb4 13.axb4 Ne4 14.Bb2 c5 15.Qb3 h6

up to 5…O-O as line 29

6.Qc2: The queen goes to c2 and covers e4 – White prepares a3.
6…d6: Stockfish had 6...d5 (+0.22) ahead; 6...d6 gives away a good tenth but stays with the course's plan.
7.a3: 7.a3 puts the question to you: trade or retreat.
7…Bxc3: Watch out: you must trade here! 7...Bxc3 (+0.54) against 7...Ba5 (+5.5) – afterwards b4 and c5 trap the bishop.
8.Bxc3: White recaptures with the bishop and has the bishop pair.
8…Nbd7: The knight supports e5. Stockfish chooses 8...Nbd7 (+0.27) ahead of 8...Re8 (+0.46).
9.e3: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
9…a5: 9...a5 prevents b4 and secures c5 for your knight.
10.Be2: The bishop goes to e2 and prepares castling.
10…b6: 10...b6 prepares the bishop on b7 against the centre.
11.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal.
11…Bb7: The bishop goes to b7 and attacks the knight on f3.
12.b4: 12.b4 opens the queenside for the bishop pair.
12…axb4: You take on b4 and open the a-file.
13.axb4: White recaptures with the a-pawn and opens the a-file.
13…Ne4: The knight jumps to e4 and attacks the bishop on c3.
14.Bb2: The bishop goes to b2 and keeps the long diagonal.
14…c5: 14...c5 attacks the centre and opens the lines.
15.Qb3: The queen goes to b3 – White stands slightly better. Stockfish: level (+0.27).
15…h6: The line ends with Black's 15th move. Stockfish rates the position at +0.27 – almost level.

Line 31: 5.Nc3 O-O 6.e3 d6 7.Be2 e5 8.O-O Bf5 9.Nh4 Bd7 10.Nf3 Bf5

up to 5…O-O as line 30

6.e3: 6.e3 supports d4 and opens the bishop on f1.
6…d6: Stockfish had 6...Bxc3 (+0.13) ahead; 6...d6 gives away just under a tenth.
7.Be2: The bishop goes to e2 and prepares castling.
7…e5: A move of Stockfish: the pawn against d4. Stockfish sees 7...Re8 and 7...e5 as equal (+0.17).
8.O-O: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
8…Bf5: The bishop goes to f5 and eyes b1.
9.Nh4: The knight attacks your bishop on f5.
9…Bd7: The bishop retreats to d7 and stays in the game.
10.Nf3: The knight returns to f3 and covers e5.
10…Bf5: The bishop goes to f5 again – the moves repeat. Stockfish: level (+0.17). (transposition)

Chapter 3: 5.e3

Line 32: 5.e3 O-O 6.Bd3 Bxd2 7.Qxd2 d6 8.Nc3 e5 9.Bc2 Na6 10.O-O Bg4 11.Ng5 h6 12.Nge4 Nxe4 13.Bxe4 c6 14.d5 f5 15.Bc2 e4

5.e3: Stockfish's first choice in the starting position (+0.28): White sets up calmly.
5…O-O: You castle. Stockfish had 5...b6 (+0.2) and 5...Bxd2 (+0.26) ahead; 5...O-O gives away just under two tenths.
6.Bd3: The bishop goes to d3 and eyes h7.
6…Bxd2: You trade the bishop. Stockfish had 6...d5 (+0.21) ahead; 6...Bxd2 (+0.26) is the second choice. The players trade in three games out of four.
7.Qxd2: The queen recaptures on d2 and connects the pieces.
7…d6: Again d6 and e5. Stockfish had 7...d5 (+0.25) ahead; 7...d6 gives away a good tenth.
8.Nc3: The knight goes to c3 and covers e4 and d5.
8…e5: Stockfish chooses 8...e5 (+0.37) just ahead of 8...d5 (+0.39).
9.Bc2: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
9…Na6: The knight goes to a6 and on to b4.
10.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal.
10…Bg4: The bishop pins the knight on f3, which covers e5.
11.Ng5: The knight jumps to g5 and attacks h7.
11…h6: 11...h6 drives the knight from its attacking square on g5.
12.Nge4: The knight attacks your knight on f6.
12…Nxe4: You trade on e4 and take away one of White's attackers.
13.Bxe4: White recaptures with the bishop and eyes h7.
13…c6: 13...c6 supports d5 and takes b5 from the knight.
14.d5: 14.d5 gains space and attacks c6.
14…f5: 14...f5 attacks the bishop on e4 and opens the f-file.
15.Bc2: The bishop retreats to c2 and covers e4. Stockfish sees White slightly ahead (+0.38).
15…e4: The line ends with Black's 15th move. Stockfish rates the position at +0.25 – almost level.

Line 33: 5.e3 O-O 6.Bd3 Bxd2 7.Nbxd2 d6 8.Qc2 e5 9.O-O h6 10.h3 Re8 11.Ne4 Nxe4 12.Bxe4 exd4 13.Bh7 Kh8 14.exd4 g6 15.Rfe1 Qf8

up to 6…Bxd2 as line 32

7.Nbxd2: White recaptures with the knight and covers e4.
7…d6: Stockfish chooses 7...d6 (+0.15) ahead of 7...c5 (+0.25).
8.Qc2: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
8…e5: 8...e5 attacks the centre – the typical freeing move.
9.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal.
9…h6: 9...h6 gives the king an escape square and takes g5 from the pieces.
10.h3: 10.h3 gives the king an escape square and takes g5 from the pieces.
10…Re8: The rook goes to e8 and supports the pawn on e5.
11.Ne4: The knight attacks your knight on f6.
11…Nxe4: You trade on e4 and open the centre.
12.Bxe4: White recaptures with the bishop and eyes h7.
12…exd4: You take on d4 and open the e-file.
13.Bh7: The bishop gives check on h7 and forces your king to h8.
13…Kh8: The king goes to h8 and attacks the bishop on h7.
14.exd4: White takes on d4 and covers e5.
14…g6: 14...g6 shuts in the bishop on h7 – it has hardly any squares left.
15.Rfe1: The rook goes to e1 and covers the e-file – level.
15…Qf8: The line ends with Black's 15th move. Stockfish rates the position at 0 – almost level.

Line 34: 5.e3 O-O 6.Bxb4 Qxb4 7.Qd2 Qxd2 8.Nbxd2 d6 9.Rg1 Nc6 10.g4 e5 11.g5 Nd7 12.dxe5 Ncxe5 13.Nd4 Nc5 14.f4 Ned3 15.Bxd3 Nxd3

up to 5…O-O as line 33

6.Bxb4: White trades on b4 and simplifies the position.
6…Qxb4: Of course recapture: 6...Qxb4 (+0.42) – anything else costs a piece.
7.Qd2: The queen offers a queen trade – without queens the game is quiet.
7…Qxd2: You trade the queens. Stockfish had 7...Qe7 (+0.18) ahead; 7...Qxd2 (+0.26) gives away just under a tenth.
8.Nbxd2: White recaptures with the knight and covers e4.
8…d6: Stockfish chooses 8...d6 (+0.27) just ahead of 8...Nc6 (+0.3).
9.Rg1: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
9…Nc6: The knight comes to c6 and eyes d4 and e5.
10.g4: 10.g4 attacks on the kingside and drives your knight away.
10…e5: 10...e5 attacks the centre – your answer to the flank attack.
11.g5: 11.g5 drives your knight from f6.
11…Nd7: The knight goes to d7 and on to c5 or e5.
12.dxe5: White takes on e5 and opens the d-file.
12…Ncxe5: You recapture with the knight; it stands strongly on e5.
13.Nd4: The knight jumps to d4 and eyes b5 and f5.
13…Nc5: The knight goes to c5 and attacks d3 and e4.
14.f4: 14.f4 attacks the knight on e5 and gains space.
14…Ned3: The knight jumps to d3 with check.
15.Bxd3: White trades on d3 – a level endgame.
15…Nxd3: The line ends with Black's 15th move. Stockfish rates the position at +0.1 – almost level.

Line 35: 5.e3 O-O 6.Be2 Bxd2 7.Nfxd2 d5 8.O-O Rd8 9.Qb3 c5 10.dxc5 Nc6 11.Qa3 d4 12.b4 a5 13.b5 Nb4 14.exd4 Nc2 15.Qb2 Nxd4

up to 5…O-O as line 34

6.Be2: The bishop goes to e2 and prepares castling.
6…Bxd2: A move of Stockfish: the trade on d2. Stockfish sees 6...b6 (+0.31) and 6...Bxd2 (+0.34) as almost equal.
7.Nfxd2: Here the games of the collection end – from now on Stockfish plays on alone for both sides, up to Black's 15th move.
7…d5: 7...d5 builds a centre and attacks c4.
8.O-O: White castles short; the bishop on g2 shields the king and presses on the long diagonal.
8…Rd8: The rook goes to d8 and supports d5.
9.Qb3: The queen goes to b3 and attacks b7.
9…c5: 9...c5 attacks d4 and opens the position.
10.dxc5: White takes on c5 and wants to win a pawn.
10…Nc6: The knight comes to c6 and you have development for it.
11.Qa3: The queen goes to a3 and covers c5.
11…d4: 11...d4 opens the centre against White's king.
12.b4: 12.b4 supports the pawn on c5.
12…a5: 12...a5 attacks the pawn on b4.
13.b5: 13.b5 attacks your knight on c6.
13…Nb4: Watch out: only 13...Nb4 (+0.15) holds here – 13...d3 (+1.57) would be a serious mistake.
14.exd4: White takes on d4 and opens the position.
14…Nc2: Watch out: only 14...Nc2 (+0.28) holds here – 14...e5 (+3.14) would be a serious mistake.
15.Qb2: The queen goes to b2 and escapes the fork.
15…Nxd4: The line ends with Black's 15th move. Stockfish rates the position at +0.12 – almost level.