Chess strategy 10 to 25 moves, when players develop their armies and set up the stage for the coming battle; middlegame, the developed phase of the game; and endgame, when most of the pieces are gone and kings start to take an active part in the struggle. 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 Defence. They are catalogued in reference works such as the "Encyclopaedia of Chess Openings". It is recommended for
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,