Chess

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Chess

From left, a white king, black rook and queen, white pawn, black knight, and white bishop
Players	2
Setup time	Under one minute
Playing time	Casual games without time control last usually 10–60 minutes
Random chance	None
Skills required	Tactics, Strategy

Chess is a recreational and competitive game played between two players. Sometimes called Western chess or international chess to distinguish it from its predecessors and other chess variants, the current form of the game emerged in Southern Europe during the second half of the 15th century after evolving from similar, much older games of Indian and Persian origin. Today, chess is one of the world's most popular games, played by millions of people worldwide in clubs, online, by correspondence, in tournaments and informally.

The game is played on a square chequered chessboard with 64 squares arranged in an eight-by-eight square. At the start, each player (one controlling the white pieces, the other controlling the black pieces) controls sixteen pieces: one king, one queen, two rooks, two knights, two bishops, and eight pawns. The object of the game is to checkmate the opponent's king, whereby the king is under immediate attack (in "check") and there is no way to remove it from attack on the next move.

The tradition of organized competitive chess started in the sixteenth century and has developed extensively. Chess today is a recognized sport of the International Olympic Committee. The first official World Chess Champion, Wilhelm Steinitz, claimed his title in 1886; Viswanathan Anand is the current World Champion. Theoreticians have developed extensive chess strategies and tactics since the game's inception. Aspects of art are found in chess composition.

One of the goals of early computer scientists was to create a chess-playing machine, and today's chess is deeply influenced by the abilities of current chess programs and by the possibility to play online. In 1997, a match between Garry Kasparov, then World Champion, and a computer proved for the first time that machines are able to beat even the strongest human players.

Rules

Main article: Rules of chess

For a simple demonstration of the gameplay, see sample chess game.

Setup

Pieces at the start of a game.

Initial position. First row: rook, knight, bishop, queen, king, bishop, knight, and rook. Second row: pawns.

Chess is played on a square board of eight rows (called ranks and denoted with numbers 1 to 8) and eight columns (called files and denoted with letters a to h) of squares. The colors of the sixty-four squares alternate and are referred to as "light squares" and "dark squares". The chessboard is placed with a light square at the right hand end of the rank nearest to each player, and the pieces are set out as shown in the diagram, with each queen on its own color.

The pieces are divided, by convention, into white and black sets. The players are referred to as "White" and "Black", and each begins the game with sixteen pieces of the specified color. These consist of one king, one queen, two rooks, two bishops, two knights and eight pawns. White moves first. The players alternate moving one piece at a time (with the exception of castling, when two pieces are moved simultaneously). Pieces are moved to either an unoccupied square, or one occupied by an opponent's piece, capturing it and removing it from play. With one exception (en passant), all pieces capture opponent's pieces by moving to the square that the opponent's piece occupies.

When a king is under immediate attack by one or two of the opponent's pieces, it is said to be in check. The only permissible responses to a check are to capture the checking piece, interpose a piece between the checking piece and the king, or move the king to a square where it is not under attack. Castling is not a permissible response to a check. A move that would place the moving player's king in check is illegal. The object of the game is to checkmate the opponent; this occurs when the opponent's king is in check, and there is no way to remove it from attack.

Moves

Each chess piece has its own style of moving. The X's mark the squares where the piece can move if no other pieces are on the X's between the piece's initial position and destination. If there is an opponent's piece at the destination square, then moving piece can capture the opponent's piece. The only exception is the pawn which can only capture the white circles.

Moves of a king

Moves of a rook

Moves of a bishop

Moves of a queen

Moves of a knight

Moves of a pawn