Chess of the position. Weaknesses in the pawn structure, such as isolated, doubled, or backward pawns and , once created, are often permanent. Care must therefore be taken to avoid these weaknesses unless they are compensated by another valuable asset (for example, by the possibility of developing an attack). A chess opening is the group of initial moves of a game (the "opening moves"). Recognized sequences of opening moves are referred to as "openings" and have been given names such as the Ruy Lopez or Sicilian Defense. They are catalogued in reference works such as the "Encyclopaedia of Chess Openings". There
World Chess Championship 2013 that yield counterplay and make an exchange of rooks acceptable. After 60.Ra4, Carlsen's pawn sacrifice 60...h3 turned his f-pawn into a decisive passed pawn, and Anand resigned a few moves later. In the opening, Anand exchanged his bishop for a knight, which led to a structure similar to that of the Exchange Variation of the Ruy Lopez where Black has doubled pawns. Carlsen defended accurately, and after further exchanges the two players settled for a repetition of moves around move 30. Carlsen opted for 1.e4 for the first time in the match and the game developed into a Ruy Lopez,