Ruy Lopez, Exchange Variation grandmaster play by Emanuel Lasker, and later invigorated with new ideas by Bobby Fischer. The Exchange Variation can be a powerful psychological weapon. Black is forced to play actively, which is psychologically difficult if all one needs is a draw. Lasker's famous win against Jose Raul Capablanca in the St. Petersburg 1914 chess tournament is an example of this. With a lead in the tournament, Capablanca was intent on simplifying the game to obtain a draw, but faced with the Exchange Ruy he played too passively and was routed by Lasker as a result. 4...dxc6 is the main recapture. Black's
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