The Immortal Game was a chess game played in 1851 by Adolf Anderssen and Lionel Kieseritzky. It was played while the London 1851 chess tournament was in progress, an event in which both players participated. The Immortal Game was itself a casual game, however, not played as part of the tournament. Anderssen won the game by allowing a double rook sacrifice, a major loss of material, while also developing a mating attack with his remaining minor pieces. Despite losing the game, Kieseritzky was impressed with Anderssen's performance. Shortly after it was played, Kieseritzky published the game in La Régence, a French chess journal which he helped to edit. In 1855, Ernst Falkbeer published an analysis of the game, describing it for the first time with its sobriquet "immortal".

Chess is a board game for two players. It is sometimes called international chess or Western chess to distinguish it from related games such as xiangqi and shogi.