Phases of play are parts of a chess problem which happen, as it were, concurrently rather than consecutively.
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; see glossary of chess problems for a list.
Each problem has at least one phase: the post-key play or actual play; that is, the play after the key (the first move which leads to the problem's stipulation ("mate in two" or similar) being fulfilled). Other phases, which may or may not be present, are:
set play: play which would occur if it were the other side to move first in the diagram position (for instance, in a directmate, where it is usually White to move first, set play consists of lines where Black moves first)
try play: play after tries; that is, moves which almost meet the stipulation, but which fail, normally to a single Black defence
solutions to twins: slight variations to the problem brought about by, for example, changing the position of a piece, or switching the position of two pieces
extra solutions: some problems intentionally have more than one solution; in this case, each is a distinct phase
A problem with n phases is called an n-phase problem. So a problem with set play and three tries, for example, is a five-phase problem (since the actual solution is also a phase).
Each phase may contain a number of variations (lines arising from alternatives after the initial move of a phase; in a two-mover, for example, variations in the post-key play begin on Black's first move), but variations do not constitute distinct phases in themselves.
In many problems, interest is created from the way in which the play in different phases relate to one another. Sometimes the play in different phases has similar or contrasting motivation; sometimes the actual moves in different phases may change or transfer from one phase to another. Several basic ideas involving the relationship between different phases have been revisited again and again by composers and have acquired names; for example, in the Zagoruiko, at least two black defences are answered by different white continuations in at least three phases; in the Le Grand, in one phase move A is threatened and defence x is met by move B, while in another phase move B is threatened and defence x is met by move A; in the Lacny the black defences a, b and c are met by the white moves A, B and C respectively in one phase and by B, C and A respectively in another.
The Lacny or Lacny cycle is a chess problem theme named after Ľudovít Lačný, the first person to demonstrate the idea in 1949.
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Related Research Articles
A chess opening or simply an opening refers to the initial moves of a chess game. The term can refer to the initial moves by either side, White or Black, but an opening by Black may also be known as a defense. There are dozens of different openings, and hundreds of variants. The Oxford Companion to Chess lists 1,327 named openings and variants. These vary widely in character from quietpositional play to wild tactical play. In addition to referring to specific move sequences, the opening is the first phase of a chess game, the other phases being the middlegame and the endgame.
This page explains commonly used terms in chess in alphabetical order. Some of these 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 chess-related games, see List of chess variants.
The French Defence is a chess opening characterised by the moves:
The Babson task is a particular type of chess problem, namely, a directmate with the following properties:
White makes the only move that forces checkmate in the stipulated number of moves.
Black's defences include the promotion of a certain pawn, to either a knight, a bishop, a rook, or a queen.
If Black promotes, then White must promote a pawn to the same piece that Black just promoted to - this is the only way to force checkmate within the stipulated number of moves.
This page 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.
The Novotny is a device found in chess problems named after its discoverer Antonín Novotný. A white piece is sacrificed on a square where it could be taken by two different black pieces - whichever black piece makes the capture, it interferes with the other. It is essentially a Grimshaw brought about by a white sacrifice on the critical square.
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: a white piece sacrifices itself on a square where it could be captured by one of two similarly moving black pieces moving along a different line; whichever black piece captures, it interferes with the other. Plachutta theme is named by Joseph Plachutta (1827–1883).
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.
The Ruy Lopez, also called the Spanish Opening or Spanish Game, is a chess opening characterised by the moves:
A proof game is a type of retrograde analysis chess problem. The solver must construct a game starting from the initial chess position, which ends with a given position after a specified number of moves. A proof game is called a shortest proof game if no shorter solution exists. In this case the task is simply to construct the shortest possible game ending with the given position.
In chess problems, retrograde analysis is a technique employed to determine which moves were played leading up to a given position. While this technique is rarely needed for solving ordinary chess problems, there is a whole subgenre of chess problems in which it is an important part; such problems are known as retros.
In chess, a cross-check is a tactic in which a check is played in response to a check, especially when the original check is blocked by a piece that itself either delivers check or reveals a discovered check from another piece. Sometimes the term is extended to cover cases in which the king moves out of check and reveals a discovered check from another piece ; it does not generally apply to cases where the original checking piece is captured, but it does apply to cases where the check is actually a checkmate.
Alekhine's Defence is a chess opening that begins with the moves:
When annotating chess games, commentators frequently use widely recognized annotation symbols. Question marks and exclamation points that denote a move as bad or good are ubiquitous in chess literature. Some publications intended for an international audience, such as the Chess Informant, have a wide range of additional symbols that transcend language barriers.
Kriegspiel is a chess variant invented by Henry Michael Temple in 1899 and based upon the original Kriegsspiel developed by Georg von Reiswitz in 1812. In this game each player can see their own pieces, but not those of their opponent. For this reason, it is necessary to have a third person act as a referee, with full information about the progress of the game. When it is a player's turn he or she will attempt a move, which the referee will declare to be 'legal' or 'illegal'. If the move is illegal, the player tries again; if it is legal, that move stands. Each player is given information about checks and captures. They may also ask the referee if there are any legal captures with a pawn. Since the position of the opponent's pieces is unknown, Kriegspiel is not a game with perfect information. As each player cannot see his opponent's pieces, the game is sometimes referred to as blind 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.
The following outline is provided as an overview of and topical guide to chess:
