Ruy Lopez 5.d4 exd4 6.Qxd4 and White is in . After 4...dxc6, the obvious 5.Nxe5 is weak, since 5...Qd4 6.Nf3 Qxe4+ 7.Qe2 Qxe2+ leaves White with no compensation for Black's bishop pair. There are two principal lines after 4.Bxc6 dxc6. In the late 19th and early 20th centuries, Lasker had great success with 5.d4 exd4 6.Qxd4 Qxd4 7.Nxd4. Since then, better defences for Black have been developed, and this line is considered to slightly favour Black. Jon Jacobs wrote in the July 2005 "Chess Life" (p. 21): "A database search (limited to games longer than 20 moves, both players FIDE 2300+) reveals
Ruy Lopez his 1992 match against Anatoly Karpov and won both games. By playing 6.d3 White steers clear of the Marshall Attack and any of the Anti-Marshall lines. White threatens 7.Bxc6 winning the e5-pawn leaving Black a choice of either 6...d6 or 6...b5. After 6...d6 the e5-pawn is firmly defended and Black threatens to trade off White's Ruy Lopez bishop with 7...b5 and 8...Na5. White normally continues with 7.c3 and after 8...0-0 White can choose between 9.Nbd2 or 9 Re1. Black can also play 6...b5 and after 7.Bb3 d6 (7...0-0 is a viable alternative) White has to deal with the threat of