Time control

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A time control is imposed on the tournament play of almost all two-player board games so that each round of the match can finish in a timely way and the tournament can proceed. Time controls are typically enforced by means of a game clock. Time pressure, time trouble or zeitnot is the situation of having very little time on a player's clock to complete his remaining moves.

1 Classification
2 Methodology
3 Notes and references
4 External links

[edit] Classification

The amount of time given to each player to complete their moves will vary from game to game. However most games tend to change the classification of tournaments according to the length of time given to the players^[1]. Shorter time limits, which do not afford due consideration to moves, are afforded a lesser degree of importance. Indeed shorter limits are normally given special names to distinguish them.

Lightning is the quickest limit, then Blitz. Chess has an Active category after this. As an example, for Go anything under 20 minutes can be considered blitz, while Chess generally considers something below 10 minutes to be in this category.

[edit] Methodology

The exact approach to using a game clock to regulate games varies considerably.

[edit] Sudden death

This is the simplest methodology. Once a player's main time expires he loses the game.

[edit] Overtime formats

Here the game time is separated into two basic domains. The main time, and the overtime. To switch between the two requires some trigger event. For example in Chess reaching a fixed number of moves will trigger the gain of a fixed amount of bonus time. In Go two common forms are

Canadian Byo-yomi:

After using all of his/her main time, a player must make a certain number of moves within a certain period of time — for example, twenty moves within five minutes. Typically, players stop the clock, and the player in overtime sets his/her clock for the desired interval, counts out the required number of stones and sets the remaining stones out of reach, so as not to become confused. (Some game clocks, notably the Ing clock, do not permit this option.) If twenty moves are made in time, the timer is reset to five minutes again. This is written as <main time> + <number of moves to be completed in each byo-yomi time period> in <byo-yomi time period>. ^[2] If the time period expires without the required number of stones having been played, then the player has lost on time. In Progressive Canadian Byo-yomi the required rate of play alters as we progress through additional overtime periods. ^[3]

Standard Byoyomi:

After the main time is depleted, a player has a certain number of time periods (typically around thirty seconds). After each move, the number of time periods that the player took (possibly zero) is subtracted. For example, if a player has three thirty-second time periods and takes thirty or more (but less than sixty) seconds to make a move, he loses one time period. With 60-89 seconds, he loses two time periods, and so on. If, however, he takes less than thirty seconds, the timer simply resets without subtracting any periods. This is written as <maintime> + <number of byo-yomi time periods> of <byo-yomi time period>. Using up the last period means that the player has lost on time.

[edit] Compensation (delay methods)

These methods require the use a special clock, called a delay clock. There are two main forms which provide compensation for both the time lost in physically making a move and to make it such that a player can avoid having an ever-decreasing amount of time remaining.

Bronstein delay, invented by David Bronstein. When it becomes a player's turn to move, the clock waits for the delay period before starting to subtract from the player's remaining time. For example, if the delay is five seconds, the clock waits for five seconds before counting down. The time is not accumulated. If the player moves within the delay period, no time is subtracted from his remaining time.

Fischer delay, invented by Bobby Fischer. When it becomes a player's turn to move, the delay is added to the player's remaining time. For example, if the delay is five seconds and the player has ten minutes remaining on his clock, when his clock is activated, he now has ten minutes and five seconds remaining. Time can be accumulated, so if the player moves within the delay period, his remaining time actually increases.

[edit] Penalty formats

Such methods exact a points penalty, or fine, on the player who breaches their time limit. One example occurs in Go, where the Ing Rules enforce fines on breaches of main time and overtime periods ^[4]. In tournament Scrabble the time control is standardized to 25 minutes per side with a 10-point penalty for each minute that is used in excess^{[citation needed]}. The number of extra minutes is rounded up, so that overstepping time control by 61 seconds carries a 20-point penalty.