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 most basic is to count the total value of pieces of both sides. The point values used for this purpose are based on experience; usually pawns are considered worth one point, knights and bishops about three points each, rooks about five points (the value difference between a rook and a bishop being known as the exchange), and queens about nine points. In the endgame, the king is generally more powerful than a minor piece but less powerful than a rook, thus it is sometimes assigned a fighting value of four points. These basic values are then modified by other factors like position of the piece (for example, advanced pawns are usually more valuable than those on initial positions), coordination between pieces (for example, a pair of bishops usually coordinates better than the pair of a bishop and knight), or type of position (knights are generally better in closed positions with many pawns while bishops are more powerful in open positions).