A chess clock is a device that comprises two adjacent clocks with buttons to stop one clock while starting the other, so that the two clocks never run simultaneously. The clocks are used in games where the time is allocated between two parties. The purpose is to keep track of the total time each party takes and prevent delays. Parties may take more or less time over any individual move.

Chess is a board game for two players. It is sometimes called international chess or Western chess to distinguish it from related games such as xiangqi and shogi.