K) 4....Nxe4 5.Qxd4 Nf6 6.Nc3!

Position after 6.Nc3

   Soren Galberg-Lund may have been the first to point out in print the importance of developing the Knight before the Bishop, but Frank Marshall and Carlos Torre had obviously figured this out by 1924. Even today, many masters reach the main lines via 6.Bg5?! and most published analysis does not discuss the importance of this move order, which avoids the problems with 6.Bg5?! Nc6 7.Qh4 d5! in line J. 

   After 6.Nc3 Black usually transposes to the generally recognized main lines with 6....Be7, but he can also play 6....Nc6 7.Qh4 Bb4 leading to unique positions which favor White. One line that White should be aware of is K3a, where Black plays 7....d5 before White can castle queenside, thus forcing exchanges. While White certainly retains some advantage in the K3a line, it would probably be difficult to exploit in high level competition. The lines below all follow upon 1.e4 e5 2.Bc4 Nf6 3.d4 exd4 4.Nf3 Nxe4 5.Qxd4 Nf6 6.Nc3!

K1) 6....d5 7.Bxd5!? (Better is simply 7.Nxd5! Nxd5 8.Bxd5 +=, but the Bishop capture is of interest due to transpositions from other lines.) 

K1a) 7....Nxd5 8.Nxd5

K1a1) 8....c6? 9.Qe5+ ±

K1a2) 8....Be6 9.c4 c6 10.Bg5

K1a2a) 10....Qd7?! 11.O–O–O! cxd5 (11...f6 12.Nxf6+ gxf6 13.Qxf6 Bg7 14.Qf4 +-) 12.cxd5 Qc7+ (12...f6 13.Rhe1 Nc6 14.Qe4 ±; 12...h6 13.Bf4 Qc8+ 14.Kb1 Bf5+ 15.Ka1 f6 16.Rc1 ±; 12...Qc8+!? 13.Kb1 Bf5+ 14.Ka1) 13.Kb1 Bf5+ 14.Ka1 f6 15.Bxf6! Bc5 16.Qa4+ Qd7 (16...Kf8 17.Be5 Qc8 18.Qf4 ±; 16...Bd7 17.Rhe1+ Kf7 18.Qc4! Bd6 [18...Kxf6 19.Qc3+ Kg6 20.Ne5+ +-] 19.Re7+ Kf8 20.Bxg7+ Kxe7 21.Qh4+ Kf7 22.Bxh8 Bf5 23.Nd4 +-) 17.Rhe1+ Kf8 18.Qh4 Kg8 (18...Na6 19.d6 Nb4 20.Be7+ Ke8 21.Rd2 +-) 19.Be7 Na6 (19...Bb6 20.Ne5 Qe8 21.d6 ±) 20.d6 h6 21.Ne5 Qe6 22.Nd3 Qf7 23.d7 ± g5 24.Bxg5 hxg5 25.Qxg5+ Qg6 26.d8Q+ +-

K1a2b) 10...Qa5+ 11.Nc3 h6 12.Bh4 Rg8 (12...Nd7 13.O-O-O +=) 13.Qe4 g5 14.Nd4 Rg6 15.Bg3 Nd7 16.O-O +=

K1a3) 8....Nc6 9.Qe4+ Be6 (9....Be7 10.Bf4 ±) 10.c4! (10.Nf4 +=) 10....Bd6 (10....Bb4+ 11.Nxb4 Nxb4 12.O-O O-O 13.Be3 +=; 10....Be7 11.Bf4 ±; 10....Nb4 11.Bg5 Qd7 12.Rd1 +-) 11.O-O (11.Bg5!?) 11....Qd7 (11....O-O? 12.Ng5!) 12.Bg5 +=

K1b) 7....Be7 8.Bf4 c6 9.Bc4 (9.Bxf7+!?? Kxf7 10.Ng5+ Ke8 11.Qc4 Rf8 12.Rd1 Qb6 13.O-O is unclear) 9....Qxd4 10.Nxd4 O-O 11.O-O-O +=

K2) 6....Be7 7.Bg5 d5 (7....O-O 8.O-O-O d5 9.Nxd5 Nxd5 10.Bxe7 Qxe7 11.Rhe1 Be6 12.Bxd5 Nc6 13.Bxc6 [13.Qa4!] 13....bxc6 14.Qc3 += Belle Computer--Herbst, USA 1984)

K2a) 8.O-O-O!?? dxc4 (Black might as well take up the challenge. Both 8....Nc6 9.Qh4 and 8....c6 9.Rhe1 transpose to lines L through N) 9.Qe3

K2a1) 9....Nbd7 10.Bxf6 gxf6 11.Rhe1 Kf8? (Best is probably 11....O-O 12.Qxe7 Qxe7 13.Rxe7 += and White has a solid edge in the ending; 11....c6 12.Nh4!) 12.Qh6+ Kg8 13.Rxe7! Qxe7 14.Nd5 +- Qd8 15.Re1! Ne5 16.Nxf6+ etc.

K2a2) 9....Nfd7 10.Nd5! Nc6 12.Bxe7 Nxe7 13.Rhe1 or 10....f6 11.Bf4 += 

K2a3) 9....Bd7! 10.Bxf6 gxf6 11.Nd5 Be6 (worse is 11....Kf8 12.Qh6+ Kg8 13.Rhe1 Be6 14.Nf6+ Bf6 15.Rd8+ Bd8 16.Nd4 when White has a strong attack) 12.Nxf6+ Bxf6 13.Rxd8+ Kxd8 14.Ng5! and while Black has a theoretical material advantage, in practice White's position is much easier to play.

K2b) 8.Nxd5! (8.Bxd5 c6 9.Bc4 +=) 8....Nxd5 (8....O-O 9.O-O-O Nxd5 10.Bxe7 Qxe7 11.Rhe1 Be6 12.Bxd5 Nc6 13.Qa4 += Radboud de Roos) 9.Qxd5?! (Better is 9.Qxg7! Bf6 10.Qxh8+ Bxh8 11.Bxd8 +-, and if 9....Rf8 10.O-O-O c6 11.Bxe7 Qxe7 12.Ng5 threatening Nxh7 or pressure along the e-file according to Radboud de Roos) 9....Qxd5 10.Bxd5 c6 11.Bb3?! (11.Bc4 +=) 11....Nd7 12.O-O-O Nc5 13.Bc4 Bxg5+ 14.Nxg5 O-O 15.Rhe1 (15.Nxf7 b5 16.Nh6+ Kh8 17.Nf7+ =) 15....h6 16.Ne4 Nxe4 17.Rxe4 Be6 = Gibbs--Littlewood, Ilford 1961. The game is recorded as 1-0 even though Black has achieved equality at this point. Clearly White's play could be improved in several ways.

K3) 6....Nc6 7.Qh4

K3a) 7....d5 +=
This advance is an attempt at easy equality. But despite the relatively balanced position, White retains a clear initiative and should gain the advantage with best play. 8.Nxd5 Nxd5 (8...Bb4+ 9.c3 Nxd5 10.Qxd8+ Nxd8 11.Bxd5 Bc5 +=; 8...Be6 9.Nxf6+ Qxf6 10.Qxf6 gxf6 11.Bb5 Rg8 12.Nd4 +=; 8...Be7 9.Bg5 Nxd5 10.0–0–0 Be6 11.Bxd5 Bxd5 12.c4 += transposes to Line L2) 9.Qxd8+ Nxd8 (9...Kxd8 10.Bxd5 Nb4 11.Bb3 Be6 12.Bg5+ Ke8 13.0–0–0 Bxb3 14.axb3 +=) 10.Bxd5 Be6 11.Be4 Bc5! (11...f5 12.Bd3 Bd6 13.Nd4 0–0 14.Bd2 f4 15.Nxe6 Nxe6 16.f3 Rfe8 17.0–0–0 Rad8 18.Rhe1 Kf7 19.Bc4 g5 20.Re2 ±) 12.0–0 f5 13.Bd3 0–0 14.Re1 h6 15.Bf4 c6 16.a3 g5 17.Bc7 g4 18.b4 Bb6 19.Bxb6 axb6 20.Nd4 Rf6 21.Nxe6 Nxe6 22.Bxf5 Rxf5 23.Rxe6 +=

K3b) 7....Ne7 +=
Black plans to transfer his Knight to g6 to harrass White's Queen and provide another defender to the Kingside. In this line, Black is also able to play the c6 and d5 pawn formation. The main problems with the line, however, are that the Knight is vulnerable to attack at g6, perhaps by h4-h5, and the maneuver does not gain any time for the defense in the long run.

K3b1) 8.Ne5?! (White seeks to punish Black immediately. The Knight attacks f7 while preventing 8....Ng6, so the move has some logic. But White does better to complete his development before moving the same piece twice.) 8....d5 9.Bg5?! (A rather desperate try to justify the previous move. Better 9.Bd3 Nf5 10.Qf4 = but White does not seem to have gained anything here over the main line.) 9....Nf5! (Best. The line 9....dxc4? 10.Rd1! Nd7 11.Qxc4 Nxe5 12.Rxd8+ Kxd8 13.Qd5+ Nd7 14.Qxf7 leads to unclear play that should favor White, while 9....Qd6 10.O-O-O! Qxe5 11.Rhe1 yields White a strong attack) 10.Bb5+ (10.Qf4 dxc4 11.Rd1 Bd6 -+; 10.Bxf6 gxf6! 11.Qh5 fxe5 12.Bxd5 Qe7 -+) 10....c6 11.Qa4 Be7! (Why should Black bother with 11....cxb5 12.Nxb5 Bc5 13.Nc7+ Kf8 14.Nxa8 Qe7 15.O-O-O) 12.Bxf6 Bxf6 13.Bxc6+ bxc6 14.Qxc6+ Kf8 15.Qxa8 Bxe5 -+

K3b2) 8.Bg5! (Simple development is best.) 8....Ng6 9.Qd4 c6 10.O-O-O Be7 11.h4! (White points up the poor placement of Black's Knight at g6.) 11....d5 12. h5 Nf8 13. h6 g6 += 14.Nxd5 cxd5 15.Bb5+ Bd7 16.Bxf6 Bxf6 17.Rhe1+ Ne6 18.Qxd5 O-O 19.Bxd7 Qb6 20.Qb3 Qxb3 21.axb3 Nc7 22.Rd6 Bh8 23.c3 a5 24.Kc2 Ra6 25.Rxa6 Nxa6 26.Bb5 Nc7 27.Bc4 Bf6 28.Rd1 Re8 29.Rd7 Re7 30.Rd6 Ne6 31.Bxe6 Rxe6 32.Rxe6 fxe6 33.Nd2 Bg5 34.Nc4 Bxh6 35.Nxa5 b6 36.Nc6 Kf7 37.b4 Kf6 38.Kd3 Bc1 39.Nd4 Bxb2 40.Kc2 1-0 Roobol--Dutreeuw, Amsterdam 2001.

K3c) 7....Bb4 8.O-O Bxc3 9.bxc3 +=
Black must surrender the two Bishops eventually or White will threaten Bg5 and Nd5. Now, though, White's dark squared Bishop becomes a monster.

K3c1) 9....d5

K3c1a) 10.Ba3!?
Black must play very precisely after this move, but he can achieve equality with careful play. Better, therefore, is 10.Rd1! below.

K3c1a1) 10....Be6 11.Rad1

K3c1a1a) 11....Qd7 12.Bb5! +=

K3c1a1b) 11....Ne4 12.Qh5! g6 (12....Nf6 13.Qg5;  12....Nxc3? 13.Bxd5! Nxd1 14.Bxe6 g6 15.Ne5! Qe7 [15....fxe6 16.Nxg6; 15....Nxe5 16.Qxe5; 15....gxh5? 16.Bxf7#] 16.Qxd1! +-) 13.Qh6 Qf6 (13....Qd7 14.Bb5!) 14.Bxd5 Nxc3!? 15.Bxc6+ bxc6 16.Rde1!? O-O-O 17.Qe3 +=

K3c1a1c) 11....Nd7! 12.Qxd8+ Nxd8 (12....Rxd8 13.Bxd5 Bxd5 14.Rxd5 f6 15.Nd4 +=) 13.Bxd5 Bxd5 14.Rxd5 Ne6 15.Ng5 +=/=

K3c1a2) 10....dxc4 11.Rad1 Nd5 12.Rfe1+ Be6 13.Qxc4

K3c1a2a) 13.... Nce7 14.Bxe7 Qxe7 15.Rxd5 (15....c6 16.Rde5 O-O [16....O-O-O 17.Qa4 +=] 17.Qe4 +=) 15....O-O 16.Qe4 h6 17.Nd4 Rae8 18.Re5 Qd6 19.Nxe6 Rxe6 20.Rxe6 Qxe6 21.Qxe6 fxe6 22.Rxe6 Rf5! =

K3c1a2b) 13...Qd7! 14.Qh4 b5! 15.c4 bxc4 16.Qg5 f6 17.Qxd5 Qxd5 18.Rxd5 Ne5! 19.Nxe5 Bxd5 20.Ng6+ Kf7 21.Nxh8+ Rxh8 22.Re7+ Kg6 23.f3 =

K3c1b) 10.Rd1! O-O (10....Qe7!? 11.a4!) 11.Bd3 h6 12.Bxh6 gxh6 13.Qxh6 Bg4 14.h3 Bh5 15.Ng5 Bxd1 16.Rxd1 Ne5 17.Bh7+ Kh8 18.Bf5+ Kg8 19.Rd4 Qe7 20.Rh4 Ng6 21.Bxg6 Qe1+ 22.Kh2 Qe5+ 23.g3 Ng4+ 24.Rxg4 Qg7 25.Bxf7+ Rxf7 26.Nxf7 Qxg4 27.hxg4 1-0 Burkett-Chessmaster 4000, 1995.

K3c2) 9....O-O 10.Bg5!
Keres says here that White has a strong attack. Not 10.Bd3?! Ne7 11.Bg5 Ng6 12.Qg3 a5 =+ as in Marshall--Torre, New York 1924 .

K3c2a) 10....d6 11.Bd3 h6 12.Bxh6 gxh6 13.Qxh6 Re8 (13....Ne5 14.Nxe5 dxe5 15.Rad1 Qe7 16.Rfe1 Re8 17.Re3 Qe6 18.Rg3+ 1-0 Claudio--Paolo, Reggio 1996) 14.Ng5 Be6 15.Rae1 Ne5 16.Bh7+ Nxh7 17.Qxh7+ Kf8 18.f4 Bxa2 19.Qh6+ Ke7 20.Nxf7 Bxf7 21.fxe5 Kd7 22.Rxf7+ Kc6 23.Qf4 b5 24.c4 Rxe5 25.Rxe5 dxe5 26.cxb5+ Kxb5 27.Qxe5+ c5 28.Qb2+ Ka5 29.Qa1+ Kb6 30.Rf6+ Kb7 31.Qa6+ Kb8 32.Qb5+ Kc7 33.Qc6+ Kb8 34.Rf1 1-0 Burkett--COMP CM4000, 1995.

K3c2b) 10....h6 11.Bxh6! gxh6 12.Qxh6 d5 13.Rad1! Bf5 (13....Ng4 14.Qh5 Be6 15.Bd5 +-) 14.Nh4 Bh7 15.Rd3! Kh8 (15....Bd3 16.Bd3 Ne5 17.Nf5 Ne8 18.Ne7+ Qe7 19.Qh7#) 16.Rg3 (16.f4!?) 16....Rg8 17.Bd3 Ne4? (17....Ne5! 18.Rg8+ Kg8 19.f4 unclear) 18.Be4 de4 19.Nf5!  1-0 Thompson--Weberg, US Correspondence 1949 (19...Qf8 20.Qf6+ Rg7 21.Rg7; 19....Rg3 20.fg3 Qg8 21.Qf6+; 19....Rg3 20.fg3 Qf8 21.Qf6+ Kg8 22.Nh6+ Collins). 

K4) 6....Qe7+ (A move that it will certainly drive White out of his preparation. Though the Queen should be poorly placed here, my analysis is not conclusive.) 7.Be3

K4a) 7...c6 8.0-0-0 (8.0-0 d5 9.Bd3 Be6 10.Rae1 Nbd7 11.Ng5 Nc5 12.f4 unclear) 8....d5 9.Bg5!? (9.Bd3 Be6 10.Rhe1 Nbd7 11.Ng5 Nc5 12.f4 is unclear)

K4a1) 9...h6? 10.Rhe1 Be6 11.Bxd5! cxd5 12.Nxd5 Nc6! 13.Bxf6 (13.Qa4!? Nxd5 14.Bxe7 Bxe7 15.Nd4 Nb6 16.Qb5 Bc4 17.Qc5±) 13...Nxd4 14.Bxe7 Nxf3 15.gxf3±

K4a2) 9...dxc4?! 10.Ne4 c5 11.Qe3 Be6 12.Qf4 Nbd7 13.Nd6+ Kd8 14.Nxb7+ Kc8 (14...Ke8? 15.Qc7) 15.Nd6+ Kd8 16.Ne5 Qxd6 17.Rxd6 Bxd6 18.Nxf7+ Bxf7 19.Qxd6 Re8 20.Rd1 Re7 21.Bxf6 gxf6 22.Qxf6 += with an unusual balance of material that should favor White in the long run.

K4a3) 9....Be6! 10.Bd3 (10.Bxd5?! cxd5 11.Nxd5 Bxd5 12.Bxf6 Qxf6 [or 12...gxf6 13.Qxd5 Bh6+ 14.Kb1 0-0 =+] 13.Qxd5 Be7 14.Qxb7 Qc6 =+) 10...h6 is unclear.

K4b) 7....Nc6 8.Qh4 (White may do better to develop in an original way here, since this move allows an early exchange of Queens. Perhaps instead 8.Qf4 d6 9.0-0-0 Ne5! [9...Be6 10.Rhe1 +=] 10.Bb3 unclear. However, Black could play 6....Nc6 7.Qh4 Qe7+, in which case this line would be forced.) 8...d5! (8...d6?! 9.0-0-0 Be6 10.Bg5 0-0-0 11.Rhe1 Qd7 12.Bb5±) 9.Nxd5 (9.Bxd5 Nxd5 10.Nxd5 Qxh4 11.Nxh4 Bd6 12.c4 Nb4=) 9...Nxd5 10.Bxd5 Qxh4 11.Bxc6+! (11.Nxh4 Nb4 12.Be4 Be7 13.c3 Bxh4 14.cxb4 0-0 15.0-0-0 Re8 16.Bf3 a6 17.Rhe1 c6=) 11...bxc6 12.Nxh4 Bd6 13.0-0-0 Be6 14.Rhe1 += White has only the slightest advantage, not quite as good as K3a above.

Line L>>>