Chess Opening Theory/1. e4/1...g6/2. d4/2...Bg7

=Modern Defence= White now has several choices of pawn structure to adopt. The most flexible move is /3. Nc3/, giving White some time before deciding. However, it denies the access to the Averbakh Variation (/3. c4/), the Geller's System(/3. c3/ and 4. Nf3) and the Three Pawns Attack (/3. c3/ and 4. f4).

/3. Nf3/ is also possible and will transpose early into the other variations. /3. h4/ is an attacking move that was discovered by Bobby Fischer. It aims to weaken Black's kingside pawn structure and make Black's king more vulnerable. Black may have difficulties castling in some lines arising from this move.

Theory table
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'''1. e4 g6 2. d4 Bg7'''