Ruy Lopez, Exchange Variation Qf6 7.Qd3. There are two "ECO" classifications for the Exchange Variation. Bibliography 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
Ruy Lopez bxc6 10.d4, or postpone d4 for the time being and play 8.d3 followed by manoeuvering the queen knight to the kingside with Nbd2–f1–g3. An alternative to 6...d6 is 6...b5 7.Bb3 Bb7. This is known as the Trajković Variation. Black may sacrifice a pawn with 8.c3 d5 9.exd5 Nxd5 10.Nxe5 Nxe5 11.Rxe5 Nf4. After 6.Re1 b5 7.Bb3, Black often plays 7...0-0. Here White can play 8.c3, but he has other moves. Alternatives are 8.a4, 8.h3, 8.d4, and 8.d3, which are often called "anti-Marshall" moves. White can also play 8.Nc3 with the idea of playing 9.Nd5 later. In the case White does