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
Libro de la invencion liberal y arte del juego del axedrez the second part, López introduces the word "gambit" and gives some openings that had not been previously published: the King's Gambit, some variations of the Bishop's Opening, and what is now known as the Steinitz Defense in the Ruy Lopez. The last two parts of the book are critical of the games of Damiano. After the moves 1.e4 e5 2.Nf3, Damiano thought that 2...Nc6 was Black's best move. López considered that inferior because of 3.Bb5. This opening is now known as the Ruy Lopez, although he did not invent it . Libro de la invencion liberal y arte del juego