Ruy Lopez that after the common retreat 4.Ba4, Black will have the possibility of breaking a future pin on his by playing ...b5. White must take some care not to fall into the Ruy Lopez, Noah's Ark Trap, in which Black traps White's on the b3-square with a ...a6, ...b5, and ...c4 pawn advance on the . Ercole del Rio, in his 1750 treatise "Sopra il giuoco degli Scacchi, Osservazioni pratiche dell'anonimo Modenese" (On the game of Chess, practical Observations by an anonymous Modenese), was the first author to mention 3...a6. However, the move became popular after it was played by Paul
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,