 Carlsen opened with his king knight as in game 1, but played 3.c4, and Anand took the pawn on the next move.Anand gained some advantage in the middlegame when Carlsen had to retreat his queen to h1 and became short on time.However, with the temporary pawn sacrifice 28.e3 (which chess Grandmaster and commentator Sergei Shipov described as "the best known, boldest and most debatable" move of 2013), Carlsen opened the position and managed to reactivate his pieces.