Chess problem

A chess problem, also called a chess composition, is a puzzle set by somebody using chess pieces on a chess board, that presents the solver with a particular task to be achieved. For instance, a position might be given with the instruction that White is to move first, and checkmate Black in two moves against any possible defense. A person who creates such problems is known as a composer. There is a good deal of specialized jargon used in connection with chess problems; see glossary of chess problems for a list.

The term "chess problem" is not sharply defined: there is no clear demarcation between chess compositions on the one hand and puzzles or tactical exercises on the other. In practice, however, the distinction is very clear. There are common characteristics shared by compositions in the problem section of chess magazines, in specialist chess problem magazines, and in collections of chess problems in book form. Not every chess problem has every one of these features, but most have several:

Problems can be contrasted with tactical puzzles often found in chess columns or magazines in which the task is to find the best move or sequence of moves (usually leading to mate or gain of material) from a given position. Such puzzles are often taken from actual games, or at least have positions which look as if they could have arisen during a game, and are used for instructional purposes. Most such puzzles fail to exhibit the above features.

Solution: 1.Rcc7! (threatening 2.Nc3)

There are various different types of chess problems:

Except for the directmates, the above are also considered forms of fairy chess insofar as they involve unorthodox rules.

In all the above types of problem, castling is assumed to be allowed unless it can be proved by retrograde analysis (see below) that the rook in question or king must have previously moved. En passant captures, on the other hand, are assumed not to be legal, unless it can be proved that the pawn in question must have moved two squares on the previous move.

There are several other types of chess problem which do not fall into any of the above categories. Some of these are really coded mathematical problems, expressed using the geometry and pieces of the chessboard. A famous such problem is the knight's tour, in which one is to determine the path of a knight that visits each square of the board exactly once. Another is the eight queens problem, in which eight queens are to be placed on the board so that none is attacking any of the others.

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Wikipedia