Chess clock

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A mechanical chess clock, between the eleven and the twelve the red falling paper is attached. The red cog next to the three indicates which of the two clockworks is running.

A chess clock is a clock with two time displays, the clockworks of which are linked together in such a way that only one clockwork can run at the same time. This is used to measure the players' thinking time during a game of chess in order to limit it as agreed. Chess clocks were developed for the game of chess, but are also used in other strategic board games for two players - for example checkers or go .


Chess board with chess clock.

For a long time chess was played without a time limit. The players were allowed to take as much time as they wanted for each move. Chess games could last for hours and sometimes even had to be interrupted and continued the next day because the players were too exhausted to continue playing.

Eventually, the desire to limit games to a time prevailed. Simple time specifications such as “x minutes for both players per game” are unfair, however, as one player could take all of the time to think about it. Therefore, each player is given their own fixed supply of cooling off time. Anyone who has used up their time without being able to finish the game has lost. The time limits for thinking can be very different: If there are several hours available for each player in tournament chess, it is typically around 30 minutes for rapid chess , around five minutes for blitz chess and only one to three minutes for bullet chess .

A simple clock is not enough to enforce the time rule, because an instrument is required that measures the two players' reflection times independently of each other . This was the trigger for a series of inventions, which for the time being reached their climax in the modern digital chess clock.


Historical chess clock

Until the second half of the 19th century, there was no limit to the time to think in chess. In 1843, for example, the French chess master Alexandre Deschapelles reported in a letter that the games of the match between Howard Staunton and Pierre Saint-Amant in the Café de la Régence in Paris had lasted an average of nine hours. Could not a game in one day due to fatigue both players completed, so it was interrupted and the stalemate continued the next day.


The first written record about the use of a device to limit the reflection time can be found in 1861 in reports about a competition between Adolf Anderssen and Ignaz von Kolisch . The device consisted of two rotating hourglasses . After a player made his move, he turned his own hourglass into the horizontal position and that of the opponent into the vertical position. If a player's hourglass ran out, he had lost the game according to the rules. Because of its impractical handling, this device was only used at major tournaments. In addition, with the clocks standardized for an unchangeable period of time, only a single game mode could be played.

At that time, exceeding the reflection time was handled less strictly than it is today, presumably because the time measurement method was rather imprecise. Cecil De Vere, for example, refused to win a losing position at the international chess tournament in Baden-Baden in 1870 because his opponent Louis Paulsen exceeded his time; the game was instead repeated by mutual agreement of the players.


In 1866, at the unofficial World Chess Championship in London (Anderssen vs. Steinitz competition ), referee- operated stopwatches were used for the first time to measure the time to think. The stopwatches increased the measuring accuracy, and the operation by the referee prevented manipulation. Losing a game by forgetting to push the watch was not possible in this way. At that time, the players could still use the previous hourglasses if they wished.

Mechanical clocks

Double watch without falling leaves

The first purely mechanical chess clock was invented by the English watchmaker Thomas Bright Wilson (1843–1915). Wilson, who was secretary of the Manchester Chess Club at the time, built it after talking to chess grandmaster Joseph Henry Blackburne . It consisted of two pendulum clocks that could be stopped alternately with a movable bar. This form of clock was first used in 1883 at the London International Tournament .

In 1899, HDB Mejer, then secretary of the Dutch Chess Association , suggested equipping the dial of the clock with a so-called falling leaf ( see below ) in order to be able to determine exactly when a player exceeded his thinking time. Such a chess clock with falling papers was first used in Germany in August 1908 at the DSB Congress in Düsseldorf. It wasn't until 1919 that these watches became the norm.

The pendulum clocks were gradually replaced by precision mechanical spring clockworks and the bar that connects the two clockworks with a rocking lever. This development culminated in the analog chess clocks in use today, which work precisely and reliably.

Digital clocks

In the 1980s, private inventors developed the first prototypes of digital chess clocks that were based on electronic circuits and powered by batteries. In 1985 Ben Bulsink, then a student at the University of Enschede in the Netherlands, built the first electronic chess clock, which was found to be good by many chess players and chess associations (the magazine of the Dutch Chess Association judged: "the perfect chess clock" ) - but it was due to the individual production by hand too expensive for large-scale use.

In 1988, the former world chess champion Robert James "Bobby" Fischer built an electronic chess clock that implemented the Fischer game mode, which he invented and named after him: Both players start with a fixed time, for each move they make, they get a certain number of seconds added time to think about it. In 1989 Fischer received US patent number 4,884,255 for the watch.

In 1992, Ben Bulsink, together with Albert Vasse and Paul Arentz, supplied the first Melody Amber chess tournament with digital chess clocks and planned their mass production. The project was a success, the three founded the company DGT Projects - "DGT" for digital game timer , "digital timepiece for games" - and the international chess federation Fédération Internationale des Échecs (FIDE) , which had become aware, concluded a 3-year Contract that DGT Projects should produce “the first official FIDE chess clock”. In 1994 DGT FIDE came onto the market, the first digital chess clock to be officially supported by FIDE.

Although digital chess clocks are now used almost without exception in high-class tournaments, they have not yet been able to assert themselves comprehensively in all classes and in the private sector. Some chess players welcome the fact that digital chess clocks, unlike analogue ones, do not emit any ticking noises, allow a time setting that is accurate to the second and offer new game modes. The others reject digital chess clocks because they are more expensive, do not make any usual ticking noises, only run on batteries and have a less original flair.

The analog chess clock

Chess clock Gardé , VEB Uhrenwerk Ruhla

An analog chess clock consists of a housing in which two separate spring clockworks are housed. The movements are wound on the back of the watch and can be fine-tuned using adjusting levers on the back.

The clock is operated by one of the two buttons on the top of the chess clock, which switch one of the clockworks on or off via a rocker. If the button or button is on top, the clock below is running and the other is stopped and vice versa. The built-in rocker ensures that both clocks cannot run at the same time. Thus, after the end of his move, a player can stop his own clock as well as start the opponent's clock with a single push on his side. If both levers of the rocker are horizontal, the clockworks stand still; this is the rest position of the clock, in which it is also before the start of the game.

Each clock shows the time passed on its dial. The falling leaf is movably attached to the top of the dial. If the minute hand moves towards the twelve, it raises the falling paper more and more until it finally no longer supports it when the twelve is exceeded and it falls back into its starting position. Before a game, the chess clock is set in such a way that the falling of the paper also means that a player has exceeded the time limit. A timeout can thus be determined very precisely. Often players complain that the opponent has exceeded their time with the exclamation “Time!” Or “Leaves!”.

There may be a situation where both players time out. This is precisely the case when a player first falls, but his opponent does not notice it. If the other player's paper falls, a special situation has arisen which is resolved in accordance with the current set of rules by giving the game a draw . For a long time, the GARDE clock shown on the right was the only chess clock approved for world championships.

The modern digital chess clock

Digital chess clock DGT2010 that is officially FIDE certified

The structure and functions of the digital chess clock are based on the analog chess clock. The differences are as follows:

Instead of two spring clockworks, the digital chess clock uses a single digital electronic clockwork. The energy supply is electrical. The available times are displayed on a double LCD display . The levers for activating the two displays correspond to those of the analog chess clock in terms of operation and function, however, a digital chess clock can usually be put to sleep by an additional button instead of by placing the rocker horizontally. There is no flag on a digital chess clock, a timeout is instead indicated by an extra symbol on the display (in the model shown here, for example, it is a flashing flag in front of the time) or, depending on the model, by an acoustic signal.

Digital chess clocks offer additional thinking time modes compared to analog chess clocks. For example, there is the Fischer mode , in which each player initially has a fixed basic thinking time and gains a time bonus after each move. Often, digital chess clocks also offer game modes for other board games, for example the Byo-Yomi for Go mode , in which each player has a fixed time to think about each move. These and similar game modes are only possible with a digital, electronic chess clock.

Blind chess clocks

Analog blind chess clock

Analog blind chess clock

A variant of the analog chess clock is the blind chess clock, which is used in games in which at least one visually impaired player is involved. In contrast to ordinary analog clocks, such a clock has a larger dial that is not covered by a glass pane. This enables the visually impaired player to feel the position of the pointer with his hand and read off the time that has elapsed. The particularly robust pointer suspension prevents the time from being adjusted. With this watch model, the falling paper makes a clearly audible noise when it falls, which enables the visually impaired player to immediately claim that the time has been exceeded.

Digital blind chess clock

The digital blind chess clock works like the digital chess clock described above. In addition, it has an announcement device and earphones through which the blind chess player is announced the time.

Using the chess clock in chess

The requirements that a chess clock must meet to be admitted to official tournaments and the rules for its use are set out by FIDE in the FIDE Rules of Chess Manual . Accordingly, the following guidelines apply:

Properties of the chess clocks

Section C.02.4 of the Official FIDE Laws of Chess literally specifies the following rules:

“Chess clocks should have a device that precisely indicates when the hour hand shows a full hour. They should have a so-called “falling flag” attached to the number twelve or another number, but always in such a way that its falling is clearly visible and makes it easier for the referees and players to check the times.
The clock should not reflect and thus make it difficult to recognize the falling leaf. It should run as quietly as possible so as not to disturb the players during the game. "

Use of chess clocks

The section on tournaments sets out the following rules for the use of a chess clock in an official game of chess:

  • Maintenance. The chess clock is an instrument of the referee. The referee must therefore ensure that the clock works correctly and must carry out time controls.
  • Setting the time. The clocks are set so that the timeout coincides with the falling of the leaf. The timeout should take place at the displayed time of 6 o'clock; In this way, the hour and minute hands can be differentiated better in the time emergency phase than if the time exceeded at 12 o'clock.
  • Position relative to the chessboard. The position of the chess clock is determined by the referee before the start of the game. Usually the clocks are positioned so that the referee can see them easily. The referee may also leave the choice of position to the players. As a rule, right-handers have little advantage if the chess clock is on their right and left-handers if it is on their left; the ability to set the watch position can therefore be particularly advantageous in lightning games. In less important games, the choice of clock is usually left to the player with the black pieces, as the white player in return has the draw advantage.
  • Late start. At the specified start time of the game, the white player's clock is started. If a player is absent and has not arrived by one hour after the start time, he has lost the game. If a player arrives late and his clock has run in the meantime, he must continue to play with the reduced cooling time displayed. From July 1, 2009, new rules apply to late start according to FIDE. After that, a player who arrives at the board after the start of the game has immediately lost this game, unless otherwise agreed in the announcement of the tournament.
  • Pressing the clock. The clock must be pressed with the same hand that was used to make the move. This prevents a player from holding the clock down or pressing it before the move is complete.
  • Belated pressing. After each move the clock of both players must run briefly. In blitz games in particular, it can happen that a player makes a move and his opponent immediately replies with a counter move without waiting for the clock to be pressed. In this case, you have to press the watch on both sides. This ensures that a player does not completely gamble on the opponent's thinking time.
  • Stop the clock. As a rule, only the referee or competition director is authorized to stop the clock. As an exception, a player may stop the clock if he asks the referee for help (e.g. if he claims a draw or if he wants to convert a pawn and the desired piece is not at hand (FIDE rule 6.13))
  • Draw offer. A player should only offer a draw if he has made a move and has not yet pressed the clock. An offer of a draw at another point in time is also valid, but can be viewed as a disruption.
  • Timed out. Exceeding the cooling off period normally results in the loss of the lot. The only exceptions to this rule are positions in which the opponent can no longer win even against the weakest game. In such positions (e.g. when a party has only one king left and the opponent exceeds the time) the game is drawn after the timeout. If a player is of the opinion that his opponent is not trying to win by normal means (but only by exceeding the time limit), he can claim a draw in a game with a normal cooling-off period in accordance with Article 10.2 of the FIDE rules, provided that he has a maximum of two minutes left Has. If the referee agrees with this view after observing the further course of the game, he can declare the game to be a draw even after the timeout. A timeout may only be claimed by the opponent or the referee (in rapid and blitz chess only by the opponent).
  • Both sides timed out. If both papers have fallen in a tournament game and it cannot be determined which one fell first, a decision is made depending on the time period of the time control mode: If the time control (e.g. on the occasion of the 40th move) is followed by another time period, the game is continued . If the two-sided timeout occurs in the last time period in which both players should have completed all remaining moves ("final spurt phase"), then the game is drawn. In important games, such a case of a timeout on both sides must not occur, since the referee is responsible for the time control and has to complain about the timeout being exceeded. Today digital chess clocks usually show which player exceeded the time first. In rapid and blitz, a game always ends in a draw if both players exceed the time.

In addition, the following rules apply, which influence the use of the watch, but are specified elsewhere in the set of rules:

  • Time penalties. Referees may impose time penalties if the players violate the rules of the game. A time penalty can mean both that the punished player's clock is set, i.e. he loses time to think it over, and that the opponent's clock is set back, that is, he gains time to think it over. Examples of triggering such time penalties are impossible moves or unsportsmanlike behavior by a player. However, a time penalty can never be so high that the punished player immediately exceeds the cooling off period.
  • Blind chess. In the case of a game against a poorly sighted or blind player, a special clock ( see above ) can be used for the game . The blind man also has the option of using an assistant who, among other things, can start the opponent's clock after a move has been made.

Using the chess clock when going

Go has different timing requirements than chess. In addition to a fixed cooling-off period for each player, as in chess, Go also knows various forms of stoppage times or extra time, called byo-yomi in Japanese . There are two basic variants:

  • In traditional Byo-Yomi there is a certain time interval, e.g. B. 30 seconds are available for each individual train.
  • In the so-called “Canadian Byo-Yomi ”, the time intervals are set for a certain number of stones, e.g. B. 15 stones in five minutes.

With analog chess clocks, the byo-yomi times have to be reset manually after each interval. Digital clocks often have program functions that do this automatically.

Game modes

A number of cooling-off modes have become established in the various board games.

  • In the usual time mode, each player receives a fixed time limit for the entire game. Five minutes for blitz chess games, 30 minutes for rapid chess games and two hours plus time allowance for tournament games are common.
  • In guillotine mode, the game is divided into several phases. In the first phases, a fixed number of moves must be made within a given time. In the final phase, a fixed quota of cooling off periods is available for the rest of the game. The fall of the falling flag after one of the first phases means here, like the fall of the blade of a guillotine, the premature end for a player. Common times are 1 h 45 min / 40 moves and 15 min / rest, 2 h / 40 moves and 1 h for the rest - the normal tournament mode - and 1 h / 40 moves, 1 h / 20 moves and 1 h for the rest .
  • In Fischer mode, players not only receive a fixed reserve of time to think about it, but also a small amount of time to think about each time the watch is pressed. This is to prevent a player, as soon as he has gained a clear time advantage, from only “lifting the opponent over time”, i.e. H. by making fast, completely ill-considered moves, you have to waste the rest of the thinking time. In fisherman mode, the weaker player can use a series of very fast moves to create a reserve of time to think about. Typical times are 3 min and 2 s / train, 25 min and 10 s / train, and 90 min and 30 s / train.
  • In the Bronstein mode, the players receive a fixed set of thinking time and a small amount of free time for each move. Only when the free reflection time is exceeded on a train is the actual reflection time supply touched. This is also referred to as “delay”, since the start of the clock is delayed by a short period of time. Common time specifications are 5 min and 3 s free / train and 25 min and 10 s free / train.
  • In the hourglass mode, the time it takes for the player to move decreases while that of the opponent increases by the same amount.

Web links

Commons : Chess clock  - collection of images, videos and audio files
Wiktionary: chess clock  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. Alex Crisovan : 1889–1989 100 Years of the Swiss Chess Federation. ( Memento of October 31, 2011 in the Internet Archive ) 1989, Zürcher AG (Zug); Online source evaluated on January 8, 2006
  2. Johannes Fischer: Chessbase Schachnachrichten - The International Chess Tournament Baden-Baden 1870 , evaluated on January 8, 2006
  3. ^ Garling Consulting Ltd., UK Company; Advertisement text from a company that sells chess items; can be viewed at: ; evaluated on January 8, 2006
  4. ^ David Hooper, Kenneth Whyld: The Oxford companion to chess. Oxford University Press, 2nd edition, USA 2005, ISBN 0-19-280049-3 , page number unknown
  5. 150 Years of the Chess Federation in North Rhine-Westphalia , publisher Schachbund NRW, page 12.
  6. Patent US4884255 : Published January 8, 2006 , inventor: Robert J. Fischer.
  7. ^ History of the clocks on, accessed July 10, 2015
  8. FIDE Handbook . From:, accessed June 23, 2014
  9. FIDE Handbook - 5.1 Requirements for electronic chess clocks . Retrieved June 24, 2014 from
  10. FIDE Handbook - 05. FIDE Tournament Rules . From:, accessed June 23, 2014
This version was added to the list of articles worth reading on January 10, 2006 .