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A '''chess problem''', also called a '''chess composition''', is a [[Chess puzzle|puzzle]]
{{AN chess|pos=toc}}
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**'''Two-movers''': White to move and checkmate Black in two moves against any defence.
**'''Three-movers''': White to move and checkmate Black in no more than three moves against any defence.
**'''
**'''Many-movers''': White to move and checkmate Black in a great number of moves. Problems have been composed in which White must mate Black in over 100 moves; the current record for such a composition is over 200 moves. These usually involve frequent repetitions of the same manoeuvre in order to force detrimental pawn advances.
*'''[[Helpmate]]s''': Black to move first cooperates with White to get Black's own king mated in a specified number of moves.
*'''[[Selfmate]]s''': White moves first and forces Black (in a specified number of moves) to checkmate White.
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*'''[[Endgame study|Studies]]''': an orthodox problem in which the stipulation is that White to play must win or draw. Almost all studies are [[Chess endgame|endgame]] positions. Studies are composed chess problems, but because their stipulation is open-ended (the win or draw does not have to be achieved within any particular number of moves) they are usually thought of as distinct from problems and as a form of composition that is closer to the puzzles of interest to over-the-board players. Indeed, composed studies have often extended our knowledge of endgame theory. But again, there is no clear dividing line between the two kinds of positions.
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 {{em|not}} to be legal, unless it can be proved that the pawn to be captured must have moved two squares on the previous move.<ref name="Codex">{{
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 chess problem|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 puzzle|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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*The problem should be economical.<ref>Iqbal, A. (2008). Evaluation of Economy in a Zero-sum Perfect Information Game, The Computer Journal, Oxford University Press, Vol. 51, No. 4, pp. 408–418, {{doi|10.1093/comjnl/bxm060}}. Online ISSN 1460-2067, Print ISSN 0010-4620. http://comjnl.oxfordjournals.org/content/51/4/408.abstract {{Webarchive|url=https://web.archive.org/web/20160608122007/http://comjnl.oxfordjournals.org/content/51/4/408.abstract |date=2016-06-08 }}</ref> There are several facets to this desideratum. For one thing, 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. For another, the problem should not employ more moves than is needed to exhibit the particular theme(s) at its heart; if the theme can be shown in fewer moves, it should be.
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{{Chess diagram
| tright
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The key move is 1.Rh1. This is difficult to find because it makes no threat – instead, it puts Black in [[zugzwang]], a situation in which the player must move, yet every move leads to a disadvantage. Each of Black's nineteen legal replies allows an immediate mate. For example, if Black defends with 1...Bxh7, the d5-square is no longer guarded, and White mates with 2.Nd5#. Or if Black plays 1...Re5, Black blocks that escape square for his king allowing 2.Qg4#. If Black plays 1...Rf6, then 2.Rh4#. Yet if Black could only pass (i.e., make no move at all), White would have no way to mate on his second move. The full solution is as follows:
:1 Rh1{{chesspunc|!}} and now:
::1...Bxh7, 2.Nd5# (unguards d5)
::1...Bf7, 2.Qf5# (interferes with rook’s guard of f5)
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| White mates in one move!
}}
==Abbreviations==
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Just as in over-the-board play, the titles [[Grandmaster (chess)|Grandmaster]], [[FIDE Titles|International Master]] and [[FIDE Titles|FIDE Master]] are awarded by FIDE via the [[Permanent Commission of the FIDE for Chess Compositions]] (PCCC) for especially distinguished problem and study composers and solvers (unlike over-the-board chess, however, there have not been any women-only equivalents to these titles in problem chess).
For composition, the International Master title was established in 1959, with [[André Chéron (chess player)|André Chéron]], [[Arnoldo Ellerman]], [[Alexander Gerbstmann]], [[Jan Hartong]], [[Cyril Kipping]] and [[Marian Wróbel]] being the first honorary recipients. In subsequent years, qualification for the IM title, as well as for the GM title (first awarded in 1972 to [[Genrikh Gasparyan|Genrikh Kasparyan]], [[Lev Loshinsky]], [[Comins Mansfield]], and [[Eeltje Visserman]]) and the FM title (first awarded 1990) has been determined on the basis of the number of problems or studies a composer had selected for publication in the [[FIDE Album]]s. These albums are collections of the best problems and studies composed in a particular three-year period, as selected by FIDE-appointed judges from submitted entries. Each problem published in an album is worth 1 point; each study is worth
For solvers, the GM and IM titles were both first awarded in 1982; the FM title followed in 1997. GM and IM titles can only be gained by participating in the official World Chess Solving Championship (WCSC): to become a GM, a solver must score at least 90 percent of the winner's points and on each occasion finish in at least tenth place three times within ten successive WCSCs. For the IM title they must score at least 80 percent of the winner's points and each time finish in at least fifteenth place twice within five successive WCSCs; alternatively, winning a single WCSC or scoring as many points as the winner in a single WCSC will earn the IM title. For the FM title, the solver must score at least 75 percent of the winners points and each time finish within the top 40 percent of participants in any two PCCC-approved solving competitions.
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==See also==
* [[Chess composer]]
* [[Glossary of chess problems]]
* [[Chess aesthetics]]
* [[Software for handling chess problems]]
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