Chess clock modes: simple delay, Fischer and Bronstein

Every chess clock is answering the same question: what happens when a player thinks for a long time. There are three common answers, they produce three quite different games, and the difference is much bigger than the three seconds involved would suggest.

Short version. Simple delay freezes your clock for a few seconds at the start of each move, so a quick reply costs you nothing. Fischer adds a few seconds after every move and lets you bank what you do not spend, so a fast player's clock can actually grow. Bronstein refunds the time you just used, up to a limit, so your clock can hold steady but never climb. Games Night has all three.

The notation first

A time control is written as two numbers: 5+3 means five minutes to start with and three seconds per move. The first number is always minutes of starting budget. The second is the per-move number in seconds, and what it actually does depends entirely on which mode you are in. The same 5+3 behaves differently under Fischer than under Bronstein, so the mode is worth setting deliberately rather than accepting whatever the clock came with.

The baseline: a budget and nothing else

Set the per-move number to zero and you have the oldest arrangement there is. 5+0. You get your time at the start, it counts down while you think, nothing is ever added, and if it reaches zero you lose.

For a lot of casual play that is the right answer. Two players, ten minutes each, get on with it.

Its famous flaw shows up at the end. A player with a completely winning position and eight seconds left is not playing chess any more, they are playing a game about how fast their hands are. Every mode below exists because of that ending.

Simple delay: a grace period each move

Also called US delay, and the mode most American tournament players grew up with. When it becomes your turn, the clock simply does not start. It waits out the delay period, and only then begins subtracting. Move inside the grace period and the move has cost you nothing at all.

Nothing accumulates. Use less than the delay and you do not bank the difference; you just do not lose anything. Your clock can therefore hold completely steady across a fast sequence, but it can never go up.

The practical effect is that the eight-second endgame stops being a hand-speed contest. You always have the delay to actually see the board, every single move, right down to the last one.

Fischer: an increment you get to keep

After each move, a fixed number of seconds is added to your clock. 5+3 gives you five minutes and three seconds back every time you move.

The important word is keep. If you take one second over a move and the increment is three, you are two seconds better off than you were. Play a quick sequence and your clock climbs. That changes how the whole game feels: there is always a floor under you, and time spent well early can be earned back later.

It is named after Bobby Fischer, who patented a clock built around the idea, and it is now the default nearly everywhere. Practically all current FIDE tournaments use a Fischer increment, and every major online site is built on it, which is why formats like 3+2 and 15+10 are the ones people recognise.

Bronstein: the time you used, handed back

Bronstein is simple delay's close cousin, arrived at from the other direction. The clock starts counting down immediately, as it would with no delay at all. When you complete your move, the time you just spent is refunded, up to the configured maximum.

Take two seconds over a move with a three second Bronstein setting and you get two seconds back, not three: you are exactly where you started. Take five seconds and you get three back, so you are down two. You can never end a move with more time than you began it with.

Over a whole game, Bronstein and simple delay come out at the same place. The difference is what you see while you play. With simple delay the clock sits still and then starts falling, which is easier to read under pressure. With Bronstein it falls immediately and then jumps back up, which is noisier but tells you the truth about how long you actually took. Players who like to know their real thinking time prefer it; players who just want to see how much trouble they are in prefer the delay.

It is named after David Bronstein, who proposed it before Fischer's version existed, and it is the choice of players who feel that an increment you can accumulate is not really a time limit.

Which to pick

Blitz between two people who know what they are doing. 3+2 or 5+3 Fischer. This is what online blitz has trained everyone to expect.
A club night or a longer game. 10+5 or 15+10 Fischer. Long enough to think, with enough increment that nobody loses a good position to the clock.
Playing someone much stronger, or teaching. Simple delay. The grace period removes the flag-fall panic and the stronger player cannot bank time.
Anyone who wants to see their real thinking time. Bronstein, same numbers.
Kids, or a first game. A generous budget with a generous simple delay. One idea at a time is enough, and a clock that visibly waits for them is much less frightening than one that starts falling the moment it is their turn.
Something that is not chess. Fischer works well for backgammon and for a house rule on Scrabble turns. Go is the exception: Go players usually want byo-yomi, which is a different scheme again and not one of these three.

Running it on a phone or an iPad

A chess clock has an awkward job. It has to be read from both sides of a board, by two people who are not looking at it most of the time, and it has to be unmistakable in the half second they do look. That is what the chess view in Games Night is built around.

So both clocks sit on one screen rather than one per side, the per-move value is configurable rather than a short list of presets, and there is an opponent view that flips the display for the player across the table. Sound and haptics carry the state when nobody is watching the screen. The three modes are named exactly as they are above: Simple Delay, Fischer and Bronstein.

One honest limitation: this is a clock, not tournament equipment. Rated events require approved clocks and frequently do not allow a phone at the board at all. For home, club practice, teaching and casual games it is a much better clock than the one nobody remembered to bring.

Games Night is free to try on the App Store, with the full set behind a one-off purchase. No ads, no subscription.

Common questions

What does 5+3 mean on a chess clock?

Five minutes on the clock to start with, and three seconds per move. The first number is always the starting budget in minutes, the second is the per-move amount in seconds. What that second number does depends on the mode: with Fischer it is added to your clock and you keep it, with simple delay it is a grace period before your clock starts running, and with Bronstein it is the most you can be refunded.

What is the difference between a delay and an increment?

An increment adds time to your clock and you keep whatever you do not spend, so your clock can grow over the game. A delay only protects the first few seconds of each move and gives nothing back beyond that, so your clock can hold steady but never grow.

What is the difference between simple delay and Bronstein?

The arithmetic is almost identical. With simple delay your clock pauses for the delay period and only starts counting once it has passed. With Bronstein your clock starts running immediately, then the time you used is refunded up to the delay amount. Same total time, different display: simple delay is easier to read at a glance, Bronstein shows you your real thinking time.

Fischer or Bronstein, which is better?

Fischer if you want players rewarded for moving quickly, which is why almost every modern tournament and online site uses it. Bronstein or simple delay if you want the discipline of a fixed budget without losing games to a three second scramble. For a casual game, Fischer is the friendliest of the three.

Can you still lose on time with an increment?

Yes. An increment slows the bleeding, it does not stop it. If you spend more than the increment on every move, and most people do in a real game, your clock still runs down.

Can I use a phone as a clock in a rated tournament?

Generally no. Rated events require approved clock equipment and often ban phones at the board altogether, so check with the arbiter. A phone is for home, club nights, practice and casual games.

Does Games Night show both players' clocks at once?

Yes. The chess view puts both clocks on one screen, and there is an opponent view that flips the display so the player on the other side of the board can read it the right way up.