DDG Old Main Line 4.Nc3 Nf6 5.f3 Bb4 6.a3?!

6.a3 Bxc3+ 7.bxc3 used to be my main line until the early 1990s. White gets the doubled c-pawns, but what is more important, a pair of lively bishops. I used to add "!" after the move 6.a3, but now I think it should be "?!", or even "?".

Note the resemblance to the Winckelmann-Reimer Gambit (WRG) 1.e4 e6 2.d4 d5 3.Nc3 Bb4 4.a3 Bxc3+ 5.bxc3 dxe4 6.f3, where the pawn is still on c2 instead of c4.

Tom Purser pointed out that 6...Be7 transposes to 1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.f3 (Nimzo-Indian Defence, Kmoch Variation) d5 5.a3 Be7 6.e4 dxe4. The game he quoted continued is 7.fxe4 e5 8.d5 Bc5 9.Bg5 a5 (9...h6 10.Bh4) 10.Nf3, 0-1 in 40, Tal - Keres, 1959.

B	7...c5! 7...exf3 7...O-O 7...Various

7...c5!

7...c5! causes real problems for White and is the reason why White should avoid 6.a3.

8.Be2 Nc6 9.fxe4 (9.Be3) Nxe4 (9...cxd4 10.e5 Ne4! 11.cxd4 Qxd4 12.Qxd4 Nxd4 13.Bd1 -/+; 11...Nxd4 looks even better) 10.Qd3 Nf6 11.Nf3, 1-0 in 28, Heikkinen - Ranta, 1986.
8.fxe4 cxd4 (8...Nxe4 9.Qd3 Qh4+? 10.g3 Nxg3 11.Qxg3 Qe4+ 12.Be2 Qxh1? 13.Bf3 +-; 9...f5 -/+) 9.e5 Ne4 10.Qxd4 Qa5
- 11.Ne2 Nc5 12.Rb1 Nc6 13.Qe3 (13.Rb5? Nxd4 14.Rxa5 Nd3+ wins) Nxe5 -/+, Heikkinen - Kuru, corr. 1989 !. This unfinished e-mail game showed how Black can attack the weak c3-pawn.
- 11.Bb2 Nc5 12.Rd1 Nc6 13.Qg4 O-O, 0-1 in 33, Diemer - Schlensker, 1951.
- 11.Qxe4? Qxc3+ 12.Kd1 Qxa1 13.Kc2 Bd7 wins.
8.Bg5 Qa5 9.Bd2 e3 10.Bxe3 Qxc3+ 11.Kf2 cxd4 12.Bxd4 Qa5 13.Bxf6 gxf6 14.Qd4 e5 15.Qe3 Nc6 16.Bd3 Be6 17.Be4 Rd8 18.c5 Rd2+ 19.Ne2 Nd4 20.Bd3 Qc3 21.Rad1 Rb2 22.Rb1 Rxb1 23.Rxb1 Qxc5 24.Rxb7 O-O 25.Nxd4 exd4 26.Qh6 Bf5 27.Qh5 Re8 28.Qxf7+ 1-0, Brause - joker, FICS 1996.

7...exf3

7...exf3 8.Nxf3 O-O 9.Bd3

9...Nbd7 10.O-O b6 11.Qe1 Bb7 12.Ng5 Nc5 13.Rxf6 Nxd3 14.Qh4 h6 15.Rxh6 gxh6 16.Qxh6 Be4 17.Nxe4 f6 18.Qg6+ Kh8 19.Qh5+ Kg8 20.Bh6 Qd7 21.Qg6+ Kh8 22.Nxf6 Rxf6 23.Qxf6+ 1-0, Diemer - Anonymous, 1949 .
9...b6 10.O-O Bb7 11.Bg5 Nbd7 12.Ne5 h6 13.Bh4 Qe8 14.Bxf6 Nxf6 15.Rxf6! +- gxf6 16.Qg4+ Kh8 17.Qh5 Kg7 18.Qg4+ Kh8 19.Qf4
- 19...Kg7 20.Ng4 Rh8 21.Qxf6+ Kg8 22.Rf1 (22.Nxh6+ Rxh6 23.Qxh6 f5 24.Re1) Qf8 23.Bg6! Qg7 24.Bxf7+ Kh7 25.Qh4 (25.Qxe6! Rhf8 26.Rf6) Rhf8 26.Rf6 Rxf7 27.Rxh6+?? (27.Rxf7 Qxf7 28.Qxh6+ Kg8 29.Nf6+) Kg8 28.Nf6+ 0-1, Heikkinen - Väätäinen, 1994.
- 19...Kg8 20.Qxf6 would almost transpose to this WRG game: 1.e4 e6 2.d4 d5 3.Nc3 Bb4 4.a3 Bxc3+ 5.bxc3 dxe4 6.f3 exf3 7.Nxf3 b6 8.Bb5+! c6 9.Bd3 Ba6 10.c4 Nf6 11.Bg5 h6 12.Bh4 Nbd7 13.O-O O-O 14.c3 c5 15.Ne5 Qc8 16.Rxf6!! Nxf6 17.Bxf6 gxf6 18.Qg4+! Kh8 19.Qh4 Kg8 20.Qxf6 Qc7 21.Rf1! Rad8 22.Ng4 Rfe8 23.Nxh6+ Kf8 24.Qxf7+ Qxf7 25.Rxf7# 1-0, Kroggel - Horn, corr. 1993.
9...c5 10.O-O
- 10...cxd4 11.cxd4 Nbd7 12.Bg5 h6 13.Bh4 Qa5 14.Bc2 Qc3 15.Ne5 Nxe5 16.dxe5 Qe3+ 17.Kh1 Qxe5 18.Qd3 g5 19.Rae1 Ne4 20.Rxe4 Qg7 21.Bg3 f5 22.Rd4 b6 23.Re1 f4 24.Bf2 e5 25.Rxe5 f3 26.Rd6 Bf5 27.Rxf5 Qa1+ 28.Bb1 Qg7 29.Rg6 1-0, Heikkinen - Pulli, 1991.
- 10...Nc6 11.Bc2 b6 12.Qd3 g6 13.Bg5 Kg7 14.Nd2 1-0, Heikkinen - Ostrovskij, 1994.
9...h6 10.O-O Nc6 could transpose to this WRG game: 1.e4 e6 2.d4 d5 3.Nc3 Bb4 4.a3 Bxc3+ 5.bxc3 dxe4 6.f3! exf3? 7.Nxf3 +- Nf6 8.Bd3 O-O 9.O-O h6 10.Qe1! Nc6 11.Qh4! Nd5 12.Qe1 Qd6 13.c4 Nf6 14.c3 b6 15.Qh4 Ne8 16.Bxh6! gxh6 17.Qxh6 f5 18.Qg6+ Kh8 19.Ng5 Qe7 20.Be4! Qg7 21.Qh5+ Kg8 22.Bxc6 1-0, Winckelmann - Wundt, corr. 1993.

7...O-O

8.Qc2 exf3 (8...c5! 9.Bb2 Qa5 10.fxe4 cxd4 11.Nf3 e5 12.Bd3 =/+, or 10.O-O-O!?) 9.Nxf3 Nc6 10.Bd3 b6 11.O-O Qe7? 12.Bg5 h6 13.Bxf6, 1-0 in 25, Heikkinen - Chessmaster 3000, 1994.
8.Bg5 h6 9.Bh4 g5 10.Bf2 c5 11.Ra2 Qa5 12.Qb3 b6 13.h4, 1-0 in 27, Heikkinen - Puusa, 1996.

Various

7...Bd7 8.d5 c6 9.d6 c5 10.fxe4 Nxe4 11.Qg4 Qf6 (11...Bc6 12.Qxg7? Qh4+ 13.g3 Qf6) 12.Qxe4 Qxc3+ 13.Kf2 Qxa1 14.Qxb7 Qf6+? (14...Qxc1) 15.Nf3 Bc6 16.d7+ Ke7 17.Qc7 1-0, Heikkinen - Aapola, 1991. White surely was outplayed in less than 10 moves, but one blunder made by Black can still save the day.
7...Qd6 8.a4 Nc6 9.Qc2 exf3 10.Nxf3 Ng4 11.Bd3 f5 12.O-O Nxd4?! 13.cxd4 Nxh2 14.Nxh2 Qxd4+ 15.Kh1 Qxa1 16.Bb2 Qa2 17.Ra1, 1-0 in 36, Heikkinen - bobbyc, Zone 1996.
7...b6 was suggested by Andreas Walkenhorst, based on similarity with the WRG, where Bb5+ is important in closing the a8-h1 diagonal. But because Black has here also played Nf6, White can continue with 8.fxe4 Nxe4 9.Nf3 (9.Qg4!?) f5!? =/+. Brause has played 8.Bg5 Bb7 9.c5!?.