♞Reflex Chess

Chess time controls, and what the numbers mean

Two numbers and a plus sign decide whether a game takes ninety seconds or an afternoon. Here is what a pair of numbers means, which category it lands in, and where the three bodies that hand out the names disagree.

A time control is the agreement both players make before the first move: how much thinking time each of them starts with, and whether anything is added back during the game. It is written as two numbers. 3+2 is three minutes each to begin with, plus two seconds added to your own clock every time you complete a move.

The first number is minutes and the second is seconds. That trips people up constantly, because 15+10 looks like a matched pair and is not: fifteen minutes, and ten seconds a move. Chess.com writes the same thing as 15|10, and an over the board event may write it out longhand as G/15;inc10. The three spellings mean the same control.

The second number is not always an increment. Some clocks use a delay instead, which looks similar, behaves differently, and is written differently for that reason.

How two numbers become one

Nobody classifies a game by its starting time alone, because an increment can be worth more than the base. So each body folds the increment in by assuming a game length and multiplying. This is where they part company: FIDE assumes sixty moves and both big sites assume forty.

None of the three claims the estimate is what your game will actually take. It is a sorting rule, and its only job is to put a game in a category and a rating pool.

Where each body draws its lines

Three things in that list are worth saying out loud. FIDE has no bullet category at all: the Laws of Chess name Standard, Rapid and Blitz and stop, and bullet is a word that came out of online play. Chess.com's live pools stop at rapid and have no classical rating, with anything slower run as Daily correspondence, which is measured in days per move and is not on this scale at all. And Lichess is the only one of the three that publishes its cut points in seconds rather than minutes, which is why its numbers look so specific.

They also disagree about the same game. Under FIDE a 10+0 game is Blitz, because ten minutes is ten minutes or less. Chess.com calls the same game Rapid and Lichess calls it Rapid. Nobody is wrong. There is no governing body for what a website calls its rating pools.

Where the common time controls land

Every name below was computed from that body's own published rule while this page was being built, not typed in. Where the three columns differ, they differ in real life too.

When the clock runs out

Running out of time is called flagging, after the small flag on a mechanical chess clock that falls when a player's time is up. The rule is simple with one exception, and the exception is the interesting part.

Article 6.9 of the Laws of Chess says that a player who has not completed the required moves in the allotted time loses the game. Then it adds: the game is drawn if the position is such that the opponent cannot checkmate the player's king by any possible series of legal moves. So a bare king can never win on time. Neither can a king and one bishop, or a king and one knight.

The question Article 6.9 asks is the question the insufficient material rule asks: could a checkmate happen here at all. Each position below was handed to the same rules engine that runs the trainer, and where the answer is that no legal sequence could ever produce a mate, the game is already drawn and the clock has nothing to decide.

The third line is the one that surprises people. Two knights cannot force mate against a defender who is trying, but a mate position does exist and a cooperating defender could walk into it, so the game is not drawn and the flag still loses. If you have two knights and your opponent's time runs out, you win.

The rule also runs the other way round, and that half is easier to miss. What matters is whether the player who still has time could ever mate, not whether the position is level. A player with a queen and two rooks who flags against a lone king and knight draws. Events and websites differ on some edge cases here, so if it matters, read the regulations for the event you are in. The insufficient material page has the full table.

Practise where the clock is not the problemThe trainer has no clock on it. It is positions from real games with an answer straight away, which is the part of chess that time pressure takes away from you first.Open the trainer

Questions people ask

What does 3+2 mean in chess?

Three minutes on the clock at the start of the game and two seconds added to your clock every time you complete a move. The first number is always minutes and the second is always seconds. Chess.com writes the same control as 3|2.

Is bullet an official chess category?

Not under FIDE. The Laws of Chess define Standard, Rapid and Blitz and have no bullet category, so it is not a term that appears in the rules of an over the board event. It is a real and well defined category on the big websites, where it means games under three minutes.

Why does the same time control get a different name on different sites?

Because each body writes its own rule and nobody arbitrates between them. FIDE estimates a game at sixty moves and both large sites estimate forty, and the cut points differ as well. A 10+0 game is Blitz to FIDE, Rapid on Chess.com and Rapid on Lichess.

Related

Time controls sits under The clock in the reference. Nearby: