Colle System · A40

Siroccopteryx Variation

1. d4 g6 2. Nf3 Bg7 3. e3 c5 4. Bd3 cxd4 5. Nxd4 Qa5+

An early pawn trade leaves the c-file as Black's avenue and the d-file as White's - both sides get real winning chances down their own file. Black's kingside bishop takes the long diagonal. White develops with Nf3, e3, Bd3, c3, and 0-0, then plays for the e3-e4 break to free the position.

The first 4 moves, explained

• 1. d4 Stakes a claim in the centre, controlling e5, and frees the bishop and queen.
• 1... g6 Prepares the fianchetto: the bishop will take the long diagonal via g7. Theory calls this the Modern Defense.
• 2. Nf3 Develops the knight to f3, eyeing d4 and e5. It also props up the d4 pawn.
• 2... Bg7 Fianchettoes the bishop onto the long diagonal, pressuring d4 and e5 from a distance.

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