Chess Clock: Delay vs Increment
Delay pauses your countdown for a set number of seconds each move before your main time starts ticking. Increment (Fischer) adds seconds back onto your clock after every move. Both keep games from being decided purely by running out the clock — but only a digital clock can do either; analog wind-up clocks support neither.
The one thing to know: A clock's real dividing line isn't analog vs. digital, it's delay-and-increment support. Analog wind-up clocks only do a flat flag-drop time control and cannot implement delay or increment at all. Digital clocks can support both: delay (Bronstein or US/simple delay) pauses the countdown for a set number of seconds each move before the main time starts ticking; increment (Fischer) adds seconds back onto the clock after each move is made. Nearly all USCF/FIDE-rated tournaments today require a clock capable of delay or increment, which rules out plain analog clocks for rated play.
Delay, in practice
With simple/US delay (or the related Bronstein delay), each move gets a grace period — say 5 seconds — where the clock doesn't touch your main time bank at all. Move within that window and your total time never drops; move slower and only the excess beyond the delay eats into your bank. It's a cushion against a single slow move, not a way to gain extra time overall.
Increment, in practice
Fischer increment instead adds a fixed number of seconds to your clock the instant you complete a move — so if you move quickly enough, your total time can actually grow across a long game. This is why increment time controls (like "90 minutes + 30 seconds increment") are now the default at most major rated events over classic delay formats.
Why analog clocks are being phased out of rated play
A wind-up analog clock is a purely mechanical flag-drop device — there's no way to build delay or increment logic into it. As delay/increment time controls became the standard for fairness in rated games, digital clocks became a practical requirement at most USCF/FIDE events, not just a preference.
This page is general reference information about clock mechanics, not an authoritative ruling for any specific rated event's exact time-control requirement.
Frequently Asked Questions
Delay (Bronstein or simple/US delay) pauses the countdown for a set number of seconds each move before your main time starts ticking. Increment (Fischer) adds seconds back onto your clock after each move is made. Both prevent a player from losing purely on time in a long game, but they work differently — delay 'saves' unused pause time in some variants, increment always adds a fixed amount.
No. Analog wind-up clocks only support a flat flag-drop time control — they have no mechanism for delay or increment at all. Only digital clocks can run these time controls.
Almost certainly yes. Nearly all rated USCF/FIDE tournaments today require a clock capable of delay or increment, which effectively rules out plain analog clocks for rated events.
No — they're related but distinct. Increment (Fischer) adds time after every move, so your clock can actually grow over a game. Delay just pauses the countdown for a few seconds each move; it doesn't add extra time beyond that pause.
Yes — for casual games, some scholastic events, and players who prefer a classic wind-up feel where delay/increment isn't required. It's simply not the choice for most rated tournament play today.