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A chess problem, also called a chess composition, is a puzzle set by the composer using chess pieces on a chess board, which presents the solver with a particular task. For instance, a position may be given with the instruction that White is to move first, and checkmate Black in two moves against any possible defence. A chess problem fundamentally differs from over-the-board play in that the latter involves a struggle between Black and White, whereas the former involves a competition between the composer and the solver. Most positions which occur in a chess problem are 'unrealistic' in the sense that they are very unlikely to occur in over-the-board play. There is a good deal of specialized jargon used in connection with chess problems.
This glossary of chess explains commonly used terms in chess, in alphabetical order. Some of these terms have their own pages, like fork and pin. For a list of unorthodox chess pieces, see Fairy chess piece; for a list of terms specific to chess problems, see Glossary of chess problems; for a list of named opening lines, see List of chess openings; for a list of chess-related games, see List of chess variants; for a list of terms general to board games, see Glossary of board games.
A Babson task is a directmate chess problem with the following properties:
- White has only one key, or first move, that forces checkmate in the stipulated number of moves.
- Black's defences include the promotion of a certain pawn to a queen, rook, bishop, or knight.
- If Black promotes, then the only way for White towards a forced checkmate in the stipulated number of moves is to promote a pawn to the same piece to which Black promoted.
A Grimshaw is a device found in chess problems in which two pieces arriving on a particular square mutually interfere with each other. It is named after the 19th-century problem composer Walter Grimshaw. The Grimshaw is one of the most common devices found in directmates.
An Albino is a type of chess problem, "in which, at some point in the solution, a white Pawn on its starting square makes each of its four possible moves ." When a Black pawn exhibits similar activity or a quadruple defense instead of "Albino" it is termed a "Pickaninny". The Albino is, "the four possible moves of a WP [white pawn] on its initial square ," and, the Pickaninny, "the four possible moves of a BP [black pawn] on its initial square ". The latter term was coined by Frank Janet by 1916.
The Plachutta is a device found in chess problems wherein a piece is sacrificially positioned in blockade to deny coverage of multiple distant squares required by the opposition. For example, two of an opponent's bishops, queen, or rooks are defending locations through an intersection square, and an enemy unit moved into that square blocks disrupts coverage in such a way that, even if captured, the previous defensive situation cannot be restored.
A helpmate is a type of chess problem in which both sides cooperate in order to achieve the goal of checkmating Black. In a helpmate in n moves, Black moves first, then White, each side moving n times, to culminate in White's nth move checkmating Black. Although the two sides cooperate, all moves must be legal according to the rules of chess.
Checkmate is any game position in chess and other chess-like games in which a player's king is in check and there is no possible escape. Checkmating the opponent wins the game.
In the game of chess, interference occurs when the line between an attacked piece and its defender is interrupted by sacrificially interposing a piece. It is a chess tactic which seldom arises, and is therefore often overlooked. Opportunities for interference are rare because the defended object must be more valuable than the sacrificed piece, and the interposition must itself present a threat. Huczek defines interference as a tactic involving blocking moves that obstruct lines of attack. This definition may be expanded by including blocking moves that disrupt lines of defense.
In chess, en passant describes the capture by a pawn of an enemy pawn on the same rank and an adjacent file that has just made an initial two-square advance. The capturing pawn moves to the square that the enemy pawn passed over, as if the enemy pawn had advanced only one square. The rule ensures that a pawn cannot use its two-square move to safely skip past an enemy pawn.
A selfmate is a chess problem in which White, moving first, must force the unwilling Black to deliver checkmate within a specified number of moves. Selfmates were once known as sui-mates.
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.
A model mate is a type of pure mate checkmating position in chess in which:
A joke chess problem is a puzzle in chess that uses humor as a primary or secondary element. Although most chess problems, like other creative forms, are appreciated for serious artistic themes, joke chess problems are enjoyed for some twist. In some cases the composer plays a trick to prevent a solver from succeeding with typical analysis. In other cases, the humor derives from an unusual final position. Unlike in ordinary chess puzzles, joke problems can involve a solution which violates the inner logic or rules of the game.
This article covers computer software designed to solve, or assist people in creating or solving, chess problems – puzzles in which pieces are laid out as in a game of chess, and may at times be based upon real games of chess that have been played and recorded, but whose aim is to challenge the problemist to find a solution to the posed situation, within the rules of chess, rather than to play games of chess from the beginning against an opponent.
A seriesmover is a chess problem in which one side makes a series of legal moves without reply at the end of which the other side makes a single move, giving checkmate or yielding stalemate, depending on the precise stipulation. Checks cannot be given except on the last move of the series. There are various types of seriesmover:
In chess, an ideal mate is a checkmate position that is a special form of model mate. While in a model mate, each piece on the mating player's side participates in the mate, an ideal mate involves all the pieces of the mated player's as well, typically by blocking the mated king's field of movement so that it cannot escape. As in a model mate, an ideal mate also involves the mating pieces attacking the vacant squares around the mated king's exactly once, and not attacking the mated player's other pieces occupying the king's field of movement.
In chess, several checkmate patterns occur frequently enough to have acquired specific names in chess commentary. By definition, a checkmate pattern is a recognizable/particular/studied arrangements of pieces that delivers checkmate. The diagrams that follow show these checkmates with White checkmating Black.
The following outline is provided as an overview of and topical guide to chess:
In chess, an economical mate is a checkmate position such that all of the attacker's remaining knights, bishops, rooks and queens contribute to the mating attack. The attacker's king and pawns may also contribute to the mate, but their assistance is not required, nor does it disqualify the position from being an economical mate. Economical mates are of interest to chess problem composers for their aesthetic value. In real gameplay, their occurrence is incidental. Nevertheless, some notable games have concluded with an economical mate such as the Opera game, won by Paul Morphy.
References
- Dickins, Anthony (1971) [Corrected repub. of 1969 2nd ed., The Q Press, Richmond, Surrey, England]. A Guide to Fairy Chess. New York: Dover Publications Inc. ISBN 0-486-22687-5.
- Hooper, David; Whyld, Kenneth (1996) [First pub. 1992]. The Oxford Companion to Chess (2nd ed.). Oxford University Press. ISBN 0-19-280049-3.
- Pritchard, D. B. (2007). Beasley, John (ed.). The Classified Encyclopedia of Chess Variants. John Beasley. ISBN 978-0-9555168-0-1.
- Rice, John (1996). Chess Wizardry: The New ABC of Chess Problems. London: B.T. Batsford Ltd.
