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 move carries no immediate threat, Black can respond in a wide variety of ways. Traditionally, White's objective in playing the Ruy Lopez is to spoil Black's pawn structure; either way Black recaptures following the exchange on c6 will have negative features for him, though he thereby gains the . However, in modern practice, White does not always exchange bishop for knight on c6, preferring the retreat 4. Ba4 if chased by 3...a6. The theory of the Ruy Lopez is the most extensively developed of all open games, with some lines having been analysed well beyond move thirty. At nearly every