Chess is a board game for two players, called White and Black, each controlling an army of chess pieces in their color, with the objective to checkmate the opponent's king. It is sometimes called international chess or Western chess to distinguish it from related games, such as xiangqi (Chinese chess) and shogi (Japanese chess). The recorded history of chess goes back at least to the emergence of a similar game, chaturanga, in seventh century India.
Chess.com is an internet chess server and social networking website. The site has a freemium model in which some features are available for free, and others are available for accounts with subscriptions. Live online chess can be played against other users in daily, rapid, blitz or bullet time controls, with a number of chess variants also available. Chess versus a chess engine, computer analysis, chess puzzles and teaching resources are also offered.
A chess variant is a game related to, derived from, or inspired by chess. Such variants can differ from chess in many different ways. "International" or "Western" chess itself is one of a family of games which have related origins and could be considered variants of each other. Chess developed from chaturanga, from which other members of this family, such as ouk chatrang, shatranj, Tamerlane chess, shogi, and xiangqi also evolved. Many chess variants are designed to be played with the equipment of regular chess.
Computer chess includes both hardware (dedicated computers) and software capable of playing chess. Computer chess provides opportunities for players to practice even in the absence of human opponents, and also provides opportunities for analysis, entertainment and training. Computer chess applications that play at the level of a chess master or higher are available on hardware from supercomputers to smart phones. Standalone chess-playing machines are also available.
In computer chess, a chess engine is a computer program that analyzes chess or chess variant positions, and generates a move or list of moves that it regards as strongest. A chess engine is usually a back end with a command-line interface with no graphics or windowing. Engines are usually used with a front end, a windowed graphical user interface such as Chessbase or WinBoard that the user can interact with via a keyboard, mouse or touchscreen.
