Guide · Updated September 2026

Fischer increment vs US delay vs Bronstein: what's the difference?

All three give you a few seconds per move. On a tournament flyer they look almost identical. With a minute left on your clock and a won position, they behave very differently.

Need a clock on the table? TockRelay is free on the App Store and Google Play.

What is Fischer increment?

With a Fischer increment, a fixed amount of time is added to your clock after each move you make. It is named for Bobby Fischer, who patented an increment clock in 1988. It is written with a plus sign or a bar: 3+2 and 3|2 both mean three minutes per player with two seconds added per move.

The defining trait is that increment is cumulative. Move faster than the increment and your clock goes up. Play ten quick moves at one second each with a 5-second increment and you finish the sequence 40 seconds richer than you started. As long as each move takes less than the increment, your remaining time cannot shrink — which takes much of the panic out of a scramble compared with sudden death.

The flip side is that an increment does nothing to protect a move you are still thinking about. Your clock starts counting down the instant your opponent presses, and the bonus only arrives after you press in turn.

What is US delay, or simple delay?

With a delay, your clock waits a fixed number of seconds at the start of each of your moves before your main time starts running. Move within the delay and your main time does not change at all. Take longer and only the seconds past the delay come off. Wikipedia's time-control article describes this simple delay as the form of delay most often used in the United States, and US tournament notation writes it with a d: G/30 d5 is game in 30 minutes with a 5-second delay.

A delay never adds time. The best result on any single move is keeping your clock exactly where it was. You cannot bank seconds from a fast opening to spend on a hard middlegame.

What is Bronstein timing?

Bronstein timing, named after grandmaster David Bronstein, lets your main time run from the first second of your move. When you press, it adds back the time you actually used — but never more than the set amount. Spend 3 seconds with a 5-second Bronstein allowance and 3 seconds come back. Spend 12 seconds and 5 come back.

Like delay, Bronstein can never lift your clock above where it stood when the move began. It only refunds.

Same moves, three clocks: a worked example

Suppose you have exactly 5:00 left and the setting is 5 seconds. Compare two separate moves: a quick one that takes 2 seconds, and a slower one that takes 8 seconds. Here is where your clock lands after you press:

Three things stand out. On a move slower than the allowance, all three methods finish at the same time. On a move faster than the allowance, only Fischer rewards the speed. And delay and Bronstein finish identically on both moves — which is not a coincidence.

Are delay and Bronstein really the same?

In terms of the time you end up with, yes. Wikipedia notes that the two are mathematically equivalent; they only display time differently. On a delay clock your main time sits still for the first few seconds of the move, and some clocks — TockRelay included — show the delay counting down on its own. On a Bronstein clock your main time visibly ticks from the first second, then jumps back up when you press.

Which display is better is a matter of taste. Some players find the still clock calmer in time trouble. Others prefer seeing every second of their time move. The final number after the press is the same either way.

Increment is the one that is genuinely different at the board. US Chess's page on FIDE-rated events notes that the FIDE Laws treat increment and delay as interchangeable terms for calculating how much time a control provides, but as the table shows, a player who moves faster than the allowance gains time with Fischer and not with delay.

Which should you use?

• Preparing for an event? Practice exactly what it announces. If the flyer says G/30 d5, train with a 5-second delay, not a 5-second increment — the habits differ. A US Chess rules column notes that the preferred clock for any game is the one that can be set for the announced time control.
• Playing controls you know from online? The plus-sign controls such as 3+2 and 15+10 are Fischer increments, so an increment clock will feel familiar.
• Want no time banking? Choose delay or Bronstein. Every move gets the same protection, and nobody can build a reserve by rattling off quick moves.
• Teaching newer players? A short delay covers the physical act of moving a piece and pressing the clock, so handling the pieces doesn't cost newer players time.
• Uneven strength? Keep the same method for both players and give the stronger player less base time instead. That is what time odds are for.

How do you set increment, delay, or Bronstein in TockRelay?

Built-in presets cover the common cases, but a custom control takes about as long as reading this list:

1. Open the editor. On the home screen, tap New time control.
2. Enter the base time. Type each player's starting time on the keypad, for example 30:00 for game in 30.
3. Choose the increment type. Pick No increment, Increment (Fischer), Delay (US), or Bronstein.
4. Enter the seconds. Type the per-move amount, for example 00:05 for a 5-second delay.
5. Play or save. Tap Play now to start, or Save to my controls to keep it. The free version saves one basic custom control.

The editor also has a switch to add the increment before move one, and a notation switch between the 3|2, 3+2, and G/30 d5 styles so controls read the way your club writes them. For the categories these controls fall into, see chess time controls explained.