Chess problem

A chess problem, formally called a chess composition, is a puzzle set by somebody using chess pieces on a chess board, presenting 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 defence. A person who creates such problems is known as a "composer". There is a good deal of specialised jargon used in chess problems; see chess problem terminology for a list.

Beauty in chess problems

There are no official standards by which to distinguish a beautiful problem from a poor one, and judgement varies from individual to individual as well as from generation to generation, but modern taste generally recognizes the following elements as being important if a problem is to be regarded as beautiful:

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• The problem position must be legal. That is to say, the diagram must be reachable via a legal chess game which begins from the standard opening position. It is not considered a defect if the diagram can only be reached via a game containing gross blunders. Chess problems, on the whole, are not created for the purpose of practical chess training.
• The first move of the problem's solution (the key move or key) must be unique. A problem which has two keys is said to be cooked, and would not be published in any magazine. An exception is problems which intentionally have more than one solution, which compliment or contrast each other in some way - this type of problem is particularly common in helpmates.
• Some would say that, ideally, there should only be one possible white move after every black move, although this is not nearly so important. A choice of white moves other than the first move is a dual. Duals are often excusable if the problem is strong in other regards.
• The solution should be explicable in terms of a theme or themes, rather than emerging from disjointed calculation. Many of the more common themes have been given names by problemists (see chess problem terminology for a list).
• The key move of the solution should be unobvious. Obvious moves such as checks, captures, and (in directmates) moves which restrict the movement of the black king, make for bad keys. Keys which deprive the black king of some squares it could move to (flight squares) but at the same time surrender an equal or greater number of flights are acceptable. Key moves which prevent the enemy from playing a checking move are also undesirable, particularly in cases where there is no mate provided after the checking move.
• Every piece on the board should serve a purpose, either to enable the actual solution, or to exclude alternative solutions. Extra units should not be added to create "red herrings" (this is called dressing the board), except in rare cases where this is part of the theme. If the theme can be shown with fewer total units, it should be.
• The problem should exhibit economy of moves. If the theme can be shown in fewer moves, it should be.