Fischer Increment Chess Clock

Common uses for a fischer increment chess clock

Tournament games with increment
Understanding clock settings
Rapid and classical play
Setting up a digital clock correctly

The Fischer increment adds a fixed amount of time to a player's clock each time they complete a move, and unused increment accumulates. Bobby Fischer patented a chess clock implementing it in the late 1980s, motivated by the way time scrambles were degrading the quality of endgames in serious play.

Fifteen minutes plus ten seconds is a widely used rapid control and shows the increment doing its job: ten seconds a move over a forty-move endgame is nearly seven extra minutes, which is the difference between playing an endgame and racing through one.

What problem it solved

Before increment, a player in time trouble could be forced to play twenty moves in thirty seconds regardless of how complex the position was. Games were routinely decided by who could move fastest rather than who understood the position, and the resulting quality loss was a genuine complaint in serious chess.

Increment addresses that directly by guaranteeing a minimum time per move for the rest of the game. It does not eliminate time trouble, but it makes the endgame a contest of understanding rather than of hand speed.

Increment versus the two delays

Bronstein delay returns only the time actually used on the move, capped at the delay amount, so a player can never bank time. Simple delay holds the clock still for a fixed period at the start of each move before counting down. Both guarantee a minimum per-move time without letting the total rise.

Fischer increment is the only one of the three where playing quickly is rewarded with a larger clock later. That is either its main virtue or its main flaw depending on who you ask, and it is the reason some over-the-board events prefer a delay system.

Setting a physical clock

Digital clocks implement all three systems and label them inconsistently — one manufacturer's mode number is not another's. The mode also has to be set before the game rather than adjusted during it on most models.

The reliable procedure is to set the clock, then test it: make two fast moves and check whether the time rose, stayed level or fell. That takes ten seconds and catches the wrong mode before it decides a game.

How each system behaves when a player moves quickly and when they move slowly. All three guarantee a minimum time per move.

Increment and delay compared
System	Fast move	Slow move	Total can rise
Fischer increment	Clock rises	Loses time minus increment	Yes
Bronstein delay	Clock unchanged	Loses time minus delay used	No
Simple delay	Clock unchanged	Countdown starts after delay	No
No increment	Clock falls	Clock falls	No

10 seconds a move over a 40-move endgame is nearly 7 extra minutes — the difference between playing an endgame and racing through one.
Set the clock, then test it with two fast moves and watch whether the time rises, holds or falls.

Source: FIDE Laws of Chess — increment and delay time control definitions

Sources

FIDE Laws of Chess — increment and delay time control definitions , FIDE (Verify current edition) — accessed 2026-07-28

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❓ Frequently Asked Questions

What is the Fischer increment?

A fixed amount of time added to your clock each time you complete a move, which accumulates if unused. Bobby Fischer patented a clock implementing it in the late 1980s.

What problem was it meant to solve?

Games decided by hand speed rather than understanding. Before increment, a player could be forced to make twenty moves in thirty seconds regardless of how complex the position was.

How is it different from Bronstein delay?

Bronstein returns only the time actually used, capped at the delay amount, so your clock can never rise above where it started. Fischer increment accumulates, so moving quickly banks time for later.

What is simple delay?

The clock holds still for a fixed period at the start of each move before it begins counting down. Like Bronstein, it guarantees a minimum per-move time without letting the total rise.

Which system will a tournament use?

It varies by federation and event. Fischer increment is the most common in online and international play; some over-the-board events prefer a delay system precisely because it does not let players bank time.

How do I check my clock is in the right mode?

Set it, then make two fast moves and watch what happens — the time rises with Fischer increment, holds with a delay, and falls with neither. Ten seconds of testing catches the wrong mode before it decides a game.