The Pirc Defense with …g6 for Black

1.e4 d6 2.d4 Nf6 3.Nc3 g6

The Pirc Defense with 3...g6 is a hypermodern answer to 1.e4: you first leave the centre to White, put the bishop on g7, castle short and then attack White's central pawns with e5 or c5. The course is for players who want a fighting yet solid opening against 1.e4 and like to counter-attack from a compact position. White has four main roads: the Austrian Attack with 4.f4, the Classical System with 4.Nf3, the 150 Attack with 4.Be3 and Qd2, and the Byrne Variation with 4.Bg5; on top of these comes the quiet 4.g3. Against 4.f4 and 4.Nf3 you castle quickly and strike back with Nc6, e5 or c5. Against 4.Be3 the course chooses the flexible plan with c6 and b5, in which the bishop goes to g7 later. Stockfish sees White only slightly ahead in all systems – the Pirc is a fight for the centre in which you need patience.

The bishop on g7 is your most important piece: it presses on d4 and the queenside. Do not let White trade it with Bh6 without need.
Your two central strikes are e5 and c5: e5 fits when the knight is on c6 or d7, c5 especially when White puts his bishop on e2 instead of d3.
If White pushes e5, exchange with dxe5 and look for squares for your knights, such as d5 or h5, and the lever f6.
Against the classical set-up Bg4 pins the f3 knight, a defender of d4; after Bxf3 the d4 square becomes interesting for your knight.
Against attacks with Qd2 and long castling, the queenside pawn storm with c6, b5 and b4 is your quickest counterplay.
If White closes the centre with d5, your knight belongs on e7, and you prepare f5 on the kingside.