Each player begins the game with sixteen pieces: one king, one queen, two rooks, two knights, two bishops, andeight pawns. Each of the six piece types moves differently. Pieces are used to attack and capture the opponent's pieces, with the object of the game being to 'checkmate' the opponent's king by placing it under an inescapable threat of capture. In addition to checkmate, the game can be won by the voluntary resignation of one's opponent, which typically occurs when too much material is lost, or ifcheckmate appears unavoidable. A game may also result in a draw in several ways, where neither player wins. The course of the game is divided into three phases: opening, middlegame and endgame.
The first official World Chess Champion, Wilhelm Steinitz, claimed his title in 1886; the current World Champion is Viswanathan Anand. In addition to the World Championship, there are the Women's WorldChampionship, the Junior World Championship, the World Senior Championship, the Correspondence Chess World Championship, the World Computer Chess Championship, and Blitz and Rapid World Championships. The Chess Olympiad is a popular competition among teams from different nations. Online chess has opened amateur and professional competition to a wide and varied group of players. Chess is a recognizedsport of the International Olympic Committee, and international chess competition is sanctioned by the World Chess Federation. There are also many chess variants, with different rules, different pieces, and different boards.
Since the second half of the 20th century, computers have been programmed to play chess with increasing success, to the point where home computers can play chess at a very highlevel. In the past two decades computer analysis has contributed significantly to chess theory as understood by human players, particularly in the endgame. The computer Deep Blue was the first machine player to overcome a reigning World Chess Champion when it defeated Garry Kasparov in 1997.
White always moves first. After the initial move, the players alternately move one piece at atime (with the exception of castling, when two pieces are moved). Pieces are moved to either an unoccupied square or one occupied by an opponent's piece, which is captured and removed from play. With the sole exception of en passant, all pieces capture opponent's pieces by moving to the square that the opponent's piece occupies. A player may not make any move that would put or leave his king underattack. If the player to move has no legal moves, the game is over; it is either a checkmate—if the king is under attack—or a stalemate—if the king is not.
Each chess piece has its own style of moving. In the diagrams, the dots mark the squares where the piece can move if no other pieces (including one's own piece) are on the squares between the piece's initial position and its destination.
*The king moves one square in any direction. The king has also a special move which is called castling and involves also moving a rook.
* The rook can move any number of squares along any rank or file, but may not leap over other pieces. Along with the king, the rook is involved during the king's castling move.
* The bishop can move any number of squares diagonally, but may not leap overother pieces.
* The queen combines the power of the rook and bishop and can move any number of squares along rank, file, or diagonal, but it may not leap over other pieces.
* The knight moves to any of the closest squares that are not on the same rank, file, or diagonal, thus the move forms an "L"-shape: two squares vertically and one square horizontally, or two squares horizontally and one...