The knight is a piece in the game of chess, represented by a horse's head and neck. It moves two squares vertically and one square horizontally, or two squares horizontally and one square vertically, jumping over other pieces. Each player starts the game with two knights on the b- and g-files, each located between a rook and a bishop.
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.
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 White must promote a pawn to the same piece to which Black promoted in order to complete the solution.
Zugzwang is a situation found in chess and other turn-based games wherein one player is put at a disadvantage because of their obligation to make a move; a player is said to be "in zugzwang" when any legal move will worsen their position.
This glossary of chess problems explains commonly used terms in chess problems, in alphabetical order. For a list of unorthodox pieces used in chess problems, see Fairy chess piece; for a list of terms used in chess is general, see Glossary of chess; for a list of chess-related games, see List of chess variants.
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.
Grid chess is a chess variant invented by Walter Stead in 1953. It is played on a grid board. This is a normal 64-square chessboard with a grid of lines further dividing it into larger squares. A single additional rule governs Grid chess: for a move to be legal, the piece moved must cross at least one grid line.
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 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.
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.
A selfmate is a chess problem in which White, moving first, must force Black to deliver checkmate within a specified number of moves against their will. Selfmates were once known as sui-mates.
The Saavedra position is one of the best-known chess endgame studies. It is named after the Spanish priest Fernando Saavedra (1849–1922), who lived in Glasgow during the late 19th century. Though not a strong player, he spotted a win involving a dramatic underpromotion in a position previously thought to have been a draw.
A model mate is a type of pure mate checkmating position in chess in which not only is the checkmated king and all vacant squares in its field attacked only once, and squares in the king's field occupied by friendly units are not also attacked by the mating side, but all units of the mating side participate actively in forming the mating net.
In chess, a grotesque is a problem or endgame study which features a particularly unlikely or impossible initial position, especially one in which White fights with a very small force against a much larger black army. Grotesques are generally intended to be humorous.
The bishop and knight checkmate in chess is the checkmate of a lone king which can be forced by a king, a bishop, and a knight. With the stronger side to move and with perfect play, checkmate can be forced in at most thirty-three moves from any starting position where the defender cannot quickly win one of the pieces. The exception is the "stalemate trap". These exceptions constitute about 0.5% of the positions. Checkmates are possible with the defending king on any square at the edge of the board but can be forced only from positions with different material or if the defending king is in a corner controlled by the bishop or on a square on the edge next to a corner; however, mate adjacent to the corners not controlled by the bishop is only two moves deep, so it is not generally encountered unless the defending side plays inaccurately. Although this is classified as one of the four basic or elementary checkmates, it occurs in practice only approximately once in every 6,000 games.
The rook and pawn versus rook endgame is a fundamentally important, widely studied chess endgame. Precise play is usually required in these positions. With optimal play, some complicated wins require sixty moves to either checkmate, capture the defending rook, or successfully promote the pawn. In some cases, thirty-five moves are required to advance the pawn once.
In chess, a blunder is a critically bad move or other poor decision. It is usually caused by some tactical oversight, whether it be from time trouble, overconfidence or carelessness. Although blunders are most common in amateur games, all human players make them, even at the world championship level. Creating opportunities for the opponent to blunder is an important skill in over-the-board chess.
Joke chess problems are puzzles in chess that use 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.
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:
Chess on a really big board is a large chess variant invented by Ralph Betza around 1996. It is played on a 16×16 chessboard with 16 pieces and 16 pawns per player. Since such a board can be constructed by pushing together four standard 8×8 boards, Betza also gave this variant the alternative names of four-board chess or chess on four boards.
