Chess Opening Theory/1. e4/1...d6/2. d4/2...Nf6/3. Nc3/3...g6

=Pirc Defence=

3...g6
Black continues with his hypermodern plan of fianchettoing the bishop to pressure White's center, followed by castling kingside. The bishop creates a masked attack on d4, and also helps to control the center. White still has yet to make a decision about his center, and he will do so with his next move. Here White has a number of viable options; 4.f4, the aggressive Austrian Attack, further increases White's central control, preparing e5, while also supporting a kingside attack. The calm 4.Nf3, known as the Classical Variation, simply develops solidly with a central space advantage for White. 4.Be3 is a flexible & aggressive move that tends to aim for Qd2, O-O-O and a kingside pawn-storm (often known as the 150 Attack). White has many other options, such as 4.Be2 (sometimes played with the intention of 4...Bg7 5.g4, the aggressive Chinese Variation or 4...Bg7 5.h4, the Bayonet Attack), 4.Bf4, 4.h3 (an awkward-looking move that can turn aggressive), 4.f3 (often transposing to 4.Be3, with the same plan of Be3, Qd2, O-O-O), and others.

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