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,
Four Knights Game attempt for White to exploit the advantage of the first move. In the 1990s, this opening saw a renaissance, and is now seen in the praxis of players from beginner to grandmaster. The Four Knights usually leads to quiet , though there are some variations. The "ECO" codes for the Four Knights Game are C49 (Symmetrical Variation, 4.Bb5 Bb4), C48 (4.Bb5 without 4...Bb4), C47 (4.d4 and others). White's most common move is 4.Bb5, the Spanish Variation. This variation can also be reached from the Ruy Lopez, Berlin Defence. After 4.Bb5, Black has three major alternatives. The first of these is