The Universal Chess Interface (UCI) is an open communication protocol that enables chess engines to communicate with user interfaces. [1] [2]
In November 2000, the UCI protocol was released. Designed by Rudolf Huber and Stefan Meyer-Kahlen, the author of Shredder, UCI rivals the older "Chess Engine Communication Protocol" introduced with XBoard/WinBoard.
In 2002, Chessbase, the chess software company which markets Fritz, began to support UCI, which had previously been supported by only a few interfaces and engines.
As of 2021 [update] , well over 300 engines are known to directly support UCI.
By design, UCI assigns some tasks to the user interface (i.e., presentation layer) which have traditionally been handled by the engine (at the business layer) itself.[ citation needed ]
Most notably, the opening book is usually expected to be handled by the UI, by simply selecting moves to play until it is out of book, and only then starting up the engine for calculation in the resulting position. UCI does not specify any on-disk format for the opening book. Different UIs usually have their own proprietary formats.[ citation needed ]
While the UI can also take responsibility for handling endgame tablebases, this is arguably better handled in the engine itself, as having tablebase information can be useful for considering possible future positions. [3]
Stefan-Meyer Kahlen's UCI protocol in Shredder uses a variation of long algebraic notation for moves. A "nullmove" from an engine to a GUI should be sent as 0000. [4]
The uci_limitstrength parameter tells engines with this feature to play at a lower level. The uci_elo parameter specifies the Elo rating at which the engine will aim to play. Engines that have implemented uci_elo include Delfi, Fritz, Hiarcs, Houdini, Junior, Rybka, Shredder, Sjeng and Stockfish.
The UCI has been modified to play some chess variants. Some of these are: [5]
Each of these protocols may also define variants of Portable Game Notation (PGN) and Forsyth–Edwards Notation (FEN). The XBoard CECP is said to require far fewer changes to support variants. [5]
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Forsyth–Edwards Notation (FEN) is a standard notation for describing a particular board position of a chess game. The purpose of FEN is to provide all the necessary information to restart a game from a particular position.
ChessBase is a German company that develops and sells chess software, maintains a chess news site, and operates an internet chess server for online chess. Founded in 1986, it maintains and sells large-scale databases containing the moves of recorded chess games. The databases contain data from prior games and provide engine analyses of games. Endgame tablebases are also provided by the company.
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Stefan Meyer-Kahlen is a German programmer of the computer chess programs Shredder and the entire Zappa series. As of January 2017, his program has won 18 titles as World Computer Chess Champion; four of these titles were blitz championships, and one was a Chess960 championship. He also invented the Universal Chess Interface, a chess engine protocol.
Computer shogi is a field of artificial intelligence concerned with the creation of computer programs which can play shogi. The research and development of shogi software has been carried out mainly by freelance programmers, university research groups and private companies. By 2017, the strongest programs were outperforming the strongest human players.
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Top Chess Engine Championship, formerly known as Thoresen Chess Engines Competition, is a computer chess tournament that has been run since 2010. It was organized, directed, and hosted by Martin Thoresen until the end of Season 6; from Season 7 onward it has been organized by Chessdom. It is often regarded as the Unofficial World Computer Chess Championship because of its strong participant line-up and long time-control matches on high-end hardware, giving rise to very high-class chess. The tournament has attracted nearly all the top engines compared to the World Computer Chess Championship.