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
Ruy Lopez careful play White is held to gain an advantage. The best moves are 4.Nxd4 exd4 5.O-O Bc5 6.d3 c6 7.Ba4 Ne7. This defence was published in 1843 in Paul Rudolf von Bilguer's "Handbuch des Schachspiels" and explored by Henry Bird in the late 19th century. Bird played it as Black at least 25 times, scoring +9 =3 −13 (nine wins, three draws, thirteen losses). Bird's Defence was later used a few times in tournament play by Siegbert Tarrasch, Boris Spassky, and Alexander Khalifman. Although it is still sometimes seen as a surprise weapon, no strong master since Bird has adopted