Chess Clock
A device with two adjacent timers used to limit the time each player has for their moves.
Pressing a button stops one player's clock and starts the opponent's. Digital clocks can add increment or delay per move; analog clocks use a falling flag to signal time expiration.
Etymology
Games were originally played without any time limit; a time limit was suggested by Saint-Amant in 1836, sandglasses limiting each move to 20 minutes were used in the 1852 Harrwitz–Löwenthal match, and the 1861 Anderssen–Kolisch match introduced the first modern-style time limit. The purpose-built two-clock device was invented by Thomas Bright Wilson of the Manchester Chess Club and was first used in competition at the London 1883 tournament. The first digital chess clock was built in 1973 by Bruce Cheney, then an electrical-engineering student at Cornell, and the first commercially marketed digital clock was the Micromate-80, patented in 1975 by Joseph Meshi and Jeffrey R. Ponsor. Later refinements carry players' names: the delay method is the subject of a 1994 patent filed by Frank A. Camaratta Jr. and William Goichberg, while “Bronstein delay” is named after grandmaster David Bronstein.
First documented: 1883 — First competitive use of the two-clock device, London tournament
Translations
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