DDG Exchange Variation 4.Nc3 Nf6 5.f3 exf3

In the Exchange Variation 5...exf3, Black finally commits himself to win the offered pawn, and to defend against the half-open f-file.

6.Qxf3 has to be compared with the BDG Ryder Gambit: 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 exf3 5.Qxf3. If Black takes the second pawn, "White has the chance to create irritating threats against the exposed queen" [Lane].

6.Nxf3 is played almost always in practice. Having got the knight to f3 with a tempo to protect d4, White has much less to worry about than in other variations. 6...c5 is probably the only move that gives counterplay for Black; in other lines, White has the initiative, and can concentrate on active moves.

B

6...Bb4

It is most useful to compare this line with the Kmoch Variation 5...Bb4, where White has problems in developing the king's knight and bishop. Now there is no shortage of natural developing moves, like Bg5 and Bd3, and in practice White's initiative has been proved decisive. Besides, for some reason, Black often seems to voluntarily exchange the bishop to the knight on c3, even without waiting for a3. After this tempo-loss, White's game should be very easy and intuitive.

6...Bb4

A) 7.Bg5 Bxc3+

8.bxc3

B) 7.Bd3 c5 8.a3

Black can also play worse: 7...Bxc3+? 8.bxc3

C) 7.Qa4+ Nc6 8.Bg5 (8.a3 transposes) Bxc3+ 9.bxc3 O-O

D) 7.Qb3 Bxc3+ 8.Qxc3 O-O 9.Bd3 c5 10.O-O cxd4 11.Nxd4 Nc6 12.Nxc6 bxc6 13.Bg5 c5? 14.Rxf6 gxf6 15.Bxf6 Qd6 16.Rf1, 1-0 later, Heikkinen - Parkkinen, 2000, even though White missed 16.Bxh7+! Kxh7 17.Qh3+ Kg6 18.Rf1 winning.

E) 7.Qc2 Bxc3+ 8.Qxc3 Nc6 9.Bg5 O-O 10.Bd3 h6 11.Bh4 g5 12.Nxg5 hxg5 13.Bxg5 Kg7 14.O-O Qxd4+ 15.Qxd4 Nxd4 16.Bxf6+ Kh6 17.Bxd4, 1-0 in 23, Heikkinen - gordonbasha, Zone 1996.

After 6...Bb4, Genius 2 analysed two "better" moves for White. However, it was only concerned about the knight on c3, and ignored attacking chances on the kingside.

6...Be7

As the knight on f6 is the most common target of White's attack, it would seem natural to defend it with the bishop. But again, there are no convincing examples of this idea.

6...Be7 7.Bd3 O-O

7...b6 8.O-O Bb7 9.Bf4 Bd6 10.Bg5 h6 11.Bxf6 gxf6 (11...Qxf6 12.Ne5 Qg5) 12.d5 Nd7 13.dxe6 fxe6 14.Bg6+ Ke7 15.Nd4 Bc5 16.b4 Bxd4+ 17.Qxd4 Ne5? 18.Qxe5!! fxe5 19.Rf7+ Kd6 (19...Ke8 20.Rh7+ Kf8 21.Rxh8+) 20.Nb5+ 1-0, Heikkinen - Levomäki, 2001 (:-).

8.O-O

A) 8...Nc6 9.Bc2

B) 8...b6

C) 8...c6 9.Bc2 b5 10.cxb5 cxb5 11.Qd3 b4 12.Ne4 Nxe4? 13.Qxe4 f5 14.Qxa8 1-0 (14...Qb6 15.Be4!), Heikkinen - vpet, Zone 1996.

D) 8...a6 9.Bc2 b5 10.Bg5 bxc4 11.Qe1 Bb7 12.Qh4 Nbd7? 13.Bxh7+ Nxh7 14.Bxe7, 1-0 later, Heikkinen - Kaiju, 1999.

6...b6

6...b6

A) 7.Bd3

B) 7.Bg5 Bb7 8.Bf4?! Ne4 9.Bd3 Nxc3 10.bxc3 would transpose to this Owen Defence game:

1.d4 b6 2.c4 Bb7 3.f3 Nf6 4.e4 d5 5.Nc3 dxe4 6.Bg5 exf3 7.Nxf3 Ne4 8.Bf4 Nxc3 9.bxc3 e6 (DDG Deferred!) 10.Bd3 Be7 11.O-O O-O 12.Bc2 g6 13.Ne5 Nd7 14.Ng4 Bf6 15.h4 Bxh4 16.Bh6 Re8 17.Qd3 Nf6 18.Qh3 Nxg4 19.Qxg4 Bf6 20.Rxf6 Qxf6 21.Rf1 Qe7 22.Bg5 Qd7 23.Bf6 h5 24.Qg5 1-0, Heikkinen - Superville, Zone 1996.

Very similar is this ADG game: 1.e4 e6 2.d4 d5 3.Be3 dxe4 4.f3 exf3 5.Nxf3 Nf6 6.Bd3 b6 7.O-O Bb7 8.c4 Be7 9.Nc3 O-O 10.Qc2 Nbd7 11.Ng5 h6 12.Nge4 Nxe4, 0-1 in 33, Slechta - Segall, corr. 1970's.

6...c6

This can be reached from the Semi-Slav, Gunderam Gambit: 1.d4 d5 2.c4 e6 3.Nc3 c6 4. e4 dxe4 5.f3 exf3 6.Nxf3 Nf6.

6...c6 7.Bd3

A) 7...Nbd7 8.O-O Bd6 9.Qe1

B) 7...Bd6

C) 7...Be7 8.O-O O-O 9.Bc2 Nbd7 10.Qd3 Re8 11.Ng5 Nf8 12.Be3 b6 13.Rxf6 Bxf6 14.Nxh7 Nxh7 15.Qxh7+ Kf8 16.Rf1 Ke7 17.d5, 1-0 in 28, Heikkinen - Lehto, 1999.

Various