Sudden death
Sudden death is a time control in which each player has one fixed amount of time for the whole game, with no extra time added, so a player whose clock reaches zero loses on time.
Also called: sudden death time control
In a sudden death time control, each player receives a single block of time, for example fifteen minutes, to play every move of the game. There is no increment, no delay and no second period after a set number of moves. When your clock reaches zero you lose, unless your opponent cannot possibly checkmate you, in which case the game is a draw.
This is different from many classical time controls, which add time after a certain move number or after every move. Under sudden death, you must budget your minutes from the first move, because slow opening thinking can leave you with too little for the ending. Positions that are completely winning on the board can be lost simply by running out of time.
Sudden death is common in school tournaments, club rapid events and quick weekend sections, where organizers need a firm end time for each round. The phrase is also used for a tiebreak game that ends the match immediately, which is the idea behind Armageddon. Students should learn to move quickly in simple positions and save their time for critical moments.
Also worth reading is Rapid playoff. A rapid playoff is a short extra game or mini match, played at a faster time control, that decides the winner after players tie in a tournament or match.
It sits close to Time odds. Time odds is a handicap in which one player is given less time on the clock than the other, so a stronger player can face a weaker one in a more balanced game.
A neighboring idea is Time scramble. A time scramble is the stage of a game when one or both players are very short of time and must play many moves quickly, often leading to mistakes and sudden reversals.
If "Sudden death" is the format you play most, the improvement plans by rating band give a weekly routine for your rating range.
Related terms
Armageddon is a sudden death tiebreak game in which White receives more time than Black, but Black wins the game if it ends in a draw, so that exactly one player can come out ahead.
A time control is the rule that sets how much thinking time each player gets in a game, and whether extra time is added per move, which decides what kind of chess is being played.
An increment is a small amount of time added to a player clock after each move, so that thinking time never fully runs out as long as moves keep being made quickly.
A delay is a pause at the start of each turn before a clock begins counting down, so a player can use that short time without losing any from the main clock.
A chess clock is a pair of linked timers of which only one runs at a time; after each move a player presses their side to stop their own time and start the opponent's.
A time scramble is the stage of a game when one or both players are very short of time and must play many moves quickly, often leading to mistakes and sudden reversals.
Guides that go further
See whether a base time and increment counts as bullet, blitz, rapid or classical.
Average chess rating and a good chess rating
What share of active Lichess players are rated above 800, 1200, 1500, 1800 or 2000, by time control.
What a rating measures, how FIDE, Lichess, US Chess and chess.com compute theirs, and why the numbers differ.
Want to spot this in your own games?
A first lesson starts with your games: George reviews them and builds a study plan around what he finds.