Editing Chess clock (section)

==Timing methods==
{{main|Time control}}
'''Sudden death''': The simplest [[time control]] is "sudden death", in which players must make a predetermined number of moves in a certain amount of time or forfeit the game immediately. A particularly popular variant is [[blitz chess]], in which each player is given a short time, such as five minutes, on the clock in which to play the entire game.

'''Increment''' (also known as Bonus and Fischer since former World Chess Champion [[Bobby Fischer]] patented this timing method): a specified amount of time is added to the player's main time each move, unless the player's main time ran out before they completed their move. For example, if the time control is 90+30 (ninety minutes of main time per player with a thirty-second increment each move), each player gets an additional thirty seconds added to their main time for each move, unless the player's main time ran out first. Under [[FIDE]] and US Chess rules, the increment is applied to the first move as well. For example, for 3+2 each player starts with three minutes and two seconds on the first move. Not all digital clocks automatically give the increment for move one and thus for those that don't, the increment time has to be added manually to the main time so each player gets the increment for move one. In [[online chess]], players may make multiple [[premove]]s (such as moving a knight back and forth) to give them additional time to think and/or avoid running out of time.

'''Bronstein delay''' (named after Grandmaster [[David Bronstein]] who invented this timing method): this timing method adds time but, unlike Increment, the maximum amount of time is not always added. If a player expends more than the specified delay then the entire delay is added to the player's clock, but if a player moves faster than the delay, only the exact amount of time expended by the player is added. For example, if the delay is ten seconds and a player uses ten or more seconds for a move, ten seconds is added after they complete their move. If the player uses five seconds for a move, five seconds is added after they complete their move. This ensures that the main time left on the clock can never increase even if a player makes fast moves. As with Increment, the delay time is applied to the first move under FIDE and US Chess rules.

'''Simple delay''' (also known as US delay): with this timing method, the clock waits for the delay period each move before the player's main time starts counting down. For example, if the delay is ten seconds, the clock waits for ten seconds each move before the main time starts counting down.

Bronstein delay and Simple delay are very similar, but not equal. Mathematically, Bronstein delay and Simple delay are identical; the amount of time allotted to each player is equivalent at all stages of the game. For this reason, the two delays are interchangeable in the [[FIDE]] laws of chess. <ref>{{Cite web |title=E. Miscellaneous / 01. Laws of Chess / FIDE Laws of Chess taking effect from 1 January 2023 / FIDE Handbook |url=https://handbook.fide.com/chapter/E012023 |access-date=2025-02-02 |website=International Chess Federation (FIDE) |language=en}}</ref> In practice, however, Bronstein delay and Simple delay display time differently. In Bronstein delay, the amount of time is added ''after'' the move has been made; this distinction may be crucial when a player is running out of time.<ref>{{Cite web |title=Simple Delay Setting Replaces Bronstein in US Clock Rules |url=http://www.chicagopoint.com/clock2013.html |access-date=2024-01-01 |website=www.chicagopoint.com |quote=For the most part, both methods are substantially the same in terms of the amount of time players get and consume. At the end of the move, after the clock is hit, the remaining reserve time will be identical with Bronstein and Simple Delay. The difference is in the time available to complete the current move and becomes apparent when the reserve time runs down close to zero. Because Bronstein does not award the per-move allotment until after the move has been completed, you can run out of time and lose the match before getting the per-move allotment for the current move.}}</ref>  

The advantage of Bronstein delay is that a player can always quickly see exactly how much time they have for their next move without having to mentally add the main and delay time. The advantage of Simple delay is that a player can always tell whether the time that is counting down is the delay time or the main time. For example, in a game with a 5-second delay, when a player presses their clock with 1 second remaining, the clock will display with 1 second remaining, and the 5-second delay is counted separately on their next turn. In Bronstein, the 5 seconds are immediately added, and the clock will display 6 seconds. Simple delay is the form of delay most often used in the US, while Bronstein delay is the form of delay most often used in most other countries.