Correspondence chess

Correspondence chess is chess played by various forms of long-distance correspondence, usually through a correspondence chess server, through email or by the postal system; less common methods which have been employed include fax and homing pigeon. It is in contrast to over-the-board (OTB) chess, where the players sit at a chessboard at the same time (or perhaps play at the same time remotely).

Correspondence chess allows people or clubs who are geographically distant to play one another without meeting in person. These distant relationships are just one of the many distinct appeals of correspondence chess. The length of a game played by correspondence can vary depending on the method used to transmit the moves: a game played via server or by email might last no more than a few days, weeks, or months, but a game played by post between players in different countries might last several years.

Correspondence chess differs from over-the-board (OTB) play in several respects. While players in OTB chess generally play one at a time (an exception being a simultaneous exhibition), correspondence players often have several games going at once. Tournament games are played concurrently, and some players may have more than one hundred games continuing at the same time.

Time limits in correspondence play are usually between 30 and 60 days for every 10 moves (plus transmission time in postal chess). This time allows for far deeper calculation, meaning that blunders can be less frequent. Certain forms of assistance, including books, chess databases and sometimes chess programs, are often allowed. Books and databases are almost universally acceptable, but organizations vary as to whether chess engine use is permitted.

The new phenomenon of computer assistance has altered the essence of correspondence chess and in addition to profound chess knowledge and analytical discipline, the ability to interpret and guide computer analysis has become important. Given that even players with poor chess knowledge can use the strongest computer programs to analyse their games, the gap between the beginner and master player has narrowed in recent years. However, the influence of computer assistance remains controversial in both official and casual play, and consensus on the issue of whether to allow computer aid is still lacking.

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