Benoni Defense

Classical Variation, Czerniak Defense, after 2... c5, through 11. f3A79

1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6 7. Nf3 Bg7 8. Be2 O-O 9. O-O Re8 10. Nd2 Na6 11. f3

An early pawn trade leaves the c-file as White's avenue and the e-file as Black's - both sides get real winning chances down their own file. Black's kingside bishop takes the long diagonal. ...c5 and ...e6 tempt d5, then Black gets a queenside majority and the half-open e-file: ...b5 is the eternal break, White's is e4-e5.

• 1. d4 Stakes a claim in the centre, controlling e5, and frees the bishop and queen.
• 1... Nf6 Develops the knight to f6, eyeing d5 and e4.
• 2. c4 Fights for d5 from the flank - contesting the centre without committing a centre pawn.
• 2... c5 Challenges the pawn on d4 - the central tension has to resolve. Theory calls this the Benoni Defense.

Three Knights Variation, Burille Variation, Reversed TarraschA56

1. d4 Nf6 2. c4 c5 3. e3 g6 4. Nc3 Bg7 5. Nf3 O-O 6. Be2 cxd4 7. exd4 d5 8. O-O Nc6

An early pawn trade leaves the c-file as Black's avenue and the e-file as White's - both sides get real winning chances down their own file. ...d5 followed by ...Nxc3 hands White a broad pawn centre on purpose: the g7 bishop and ...c5 hammer d4 all game - the centre is a target, says Black.