Modern Defense · A04

Semi-Averbakh Variation, Polish Variation

1. Nf3 c5 2. c4 g6 3. d4 Bg7 4. e4 Qb6

Black's kingside bishop takes the long diagonal. ...g6 before anything: maximum flexibility, the g7 bishop as the anchor, and the pawn breaks chosen only after White commits.

The first 4 moves, explained

• 1. Nf3 Develops the knight to f3, eyeing d4 and e5. Theory calls this the Zukertort Opening.
• 1... c5 Fights for d4 from the flank - contesting the centre without committing a centre pawn. Theory calls this the Sicilian Invitation.
• 2. c4 Fights for d5 from the flank - contesting the centre without committing a centre pawn. Theory calls this the Symmetrical Variation.
• 2... g6 Prepares the fianchetto: the bishop will take the long diagonal via g7.

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