In the game of chess, perpetual check is a situation in which one player can force a draw by an unending series of checks. This typically arises when the player who is checking cannot deliver checkmate, and failing to continue the series of checks gives the opponent at least a chance to win. A draw by perpetual check is no longer one of the rules of chess; however, such a situation will eventually allow a draw claim by either threefold repetition or the fifty-move rule. Players usually agree to a draw long before that, however.
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 namesake "immortal".
The Opera Game was an 1858 chess game, played at an opera house in Paris. The American master Paul Morphy played against two strong amateurs: the German noble Karl II, Duke of Brunswick, and the French aristocrat Comte Isouard de Vauvenargues. It was played as a consultation game, with Duke Karl and Count Isouard jointly deciding each move for the black pieces, while Morphy controlled the white pieces by himself. The game was played in a box while an opera was performed on stage. Morphy quickly checkmated his opponents following rapid development of material, involving a queen sacrifice.
The Giuoco Piano is a chess opening beginning with the moves:
The Two Knights Defense is a chess opening that begins with the moves:
The King's Gambit is a chess opening that begins with the moves:
In chess, an X-ray or X-ray attack is a tactic where a piece indirectly controls a square from the other side of an intervening piece. Generally, a piece performing an X-ray either:
The Philidor Defence is a chess opening characterised by the moves:
The Vienna Game is an opening in chess that begins with the moves:
The Scotch Game, or Scotch Opening, is a chess opening that begins with the moves:
In chess, a pure mate is a checkmate position such that the mated king is attacked exactly once, and prevented from moving to any of the adjacent squares in its field for exactly one reason per square. Each of the squares in the mated king's field is attacked or "guarded" by one—and only one—attacking unit, or else a square which is not attacked is occupied by a friendly unit, a unit of the same color as the mated king. Some authors allow that special situations involving double check or pins may also be considered as pure mate.
The Italian Game is a family of chess openings beginning with the moves:
The Trompowsky Attack is a chess opening that begins with the moves:
The Elephant Gambit is a rarely played chess opening beginning with the moves:
The Colle System, also known as the Colle–Koltanowski System, is a chess opening system for White, popularised in the 1920s by the Belgian master Edgard Colle and further developed by George Koltanowski.
In chess, the Dragon Variation is one of the main lines of the Sicilian Defence and begins with the moves:
In chess, a desperado is a piece that is either en prise or trapped, but captures an enemy piece before it is itself captured in order to compensate the loss a little, or is used as a sacrifice that will result in stalemate if it is captured. The former case can arise in a situation where both sides have hanging pieces, in which case these pieces are used to win material prior to being captured. A desperado in the latter case is usually a rook or a queen; such a piece is sometimes also called crazy or mad.
The Exchange Variation of the Ruy Lopez is a chess opening that begins with the moves:
In chess, the Cambridge Springs Defense is a variation of the Queen's Gambit Declined that begins with the moves:
In chess, the Muzio Gambit, sometimes called the Polerio Gambit, is an opening line in the King's Gambit in which White sacrifices a knight for a large lead in development and attacking chances. It begins with the moves:
