Ruy Lopez, Exchange Variation Ruy Lopez, Exchange Variation The Exchange Variation of the Ruy Lopez is a chess opening that begins with the moves: Black may recapture on c6 with either pawn; although 4...bxc6 is playable, 4...dxc6 is almost always chosen at master level. Black has gained the at the cost of a weakened pawn structure, due to his doubled pawns on c6 and c7. White aims to reach an endgame in which he has the superior pawn structure, which may become an important factor. Thus, Black is compelled to strive for an active position, generally avoiding piece exchanges. The variation was introduced into
Open Game and preparing for d2–d4. Black's most common reply is , which usually leads to the Ruy Lopez (3.Bb5), Italian Game (3.Bc4), or Scotch Game (3.d4), though 3.Nc3 Nf6 (the Four Knights Game), often played in the late 19th to early 20th century, or, less commonly, 3...g6 or ...Bb4, (the Three Knights Game), are other possibilities. If Black instead maintains symmetry and counterattacks White's center with then the Petrov's Defense will usually result, though White can avoid the extensive theory of the Petrov by playing 3.Nc3 if he wishes. The Philidor Defence, (2...d6), largely fell out of use after World War