Ruy Lopez Blue chess computer in Game 2 of their 1997 match. Svetozar Gligorić has been the most prolific C93 player. 9...Qd7 is another variation by Smyslov. Of the variations in this section, the Berlin and Schliemann Defences are the most popular today, followed by the Classical Defence. and other less-common third moves for Black. The Cozio Defence (part of "ECO" C60), 3...Nge7, is distinctly old-fashioned and the least popular of the defences at Black's third move. Although Bent Larsen used it occasionally with success, it remains one of the least explored variations of the Ruy Lopez. The Smyslov Defence, Fianchetto Defence,
Ruy Lopez C64), 3...Bc5, is possibly the oldest defence to the Ruy Lopez, and has been played occasionally by former world champion Boris Spassky and Boris Gulko. White's most common reply is 4.c3, when Black may choose to play 4...f5, the Cordel Gambit, leading to sharp play, after which 5.d4 is considered the strongest reply. More solid for Black is instead, 4...Nf6, when 5.0-0 0-0 6.d4 Bb6 leads to the Benelux Variation. White's principal alternative to 4.c3 is 4.0-0, when Black can transpose to the Classical Berlin with 4...Nf6 or play 4...Nd4 which isn't so bad for Black. An alternative for White