Time control

A time control is a mechanism in 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.

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. [ [http://gemma.ujf.cas.cz/~cieply/GO/format.html#CLASS Instructions ] ] 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.

Methodology

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

udden death

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

Hourglass

Each player's clock starts with a specified time (eg 1 minute, 10 min etc). While Player 1 is deciding on their move, their clock time is decreasing and Player 2's clock time is increasing. This is similar to how an hourglass works, sand empties from one container, and fills into the other. Moving slowly gives your opponent extra time. The sum of both clocks will always remain the same. There is no maximum amount of time alloted for a game with this timing method, as long as both players play quickly, the game will continue until its natural end. When time runs out on one player's clock the game is over and that player loses.Fact|date=June 2008

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 can trigger the gain of a fixed amount of bonus time.

In go two common forms are:

tandard Byoyomi

After the main time is depleted, a player has a certain number of periods (for example five periods, each of thirty seconds). Now if a move is not completed within a time period, it will expire, and the next time period begins. This is written as + byo-yomi time periods> of . Using up the last period means that the player has "lost on time". In some systems, such as certain Go title matches, there is no main time; instead, the time is rounded "down" to the nearest whole increment, such as one minute, and the actual counting of time occurs toward the end of one player's time. (The term "byoyomi" literally means "counting the seconds [out loud] .")

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. If the twenty moves are made in time, the timer is reset to five minutes again. If the twenty moves are not made in time the player has "lost on time". This is written as

+ in . [http://pages.infinit.net/steven/byoyomi.htm The Origins of Canadian Byo-Yomi] 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. [ http://www.britgo.org/rules/approved.html BGA Rules page]

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. This style of time control is common on internet chess servers, where the delay is termed an "increment".

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. [http://www.usgo.org/resources/KSS.html "Ing's SST Laws of Go"] In tournament Scrabble the time control is standardized to 25 minutes per side with a 10-point penalty for each minute or part thereof that is used in excess [http://www.scrabble-assoc.com/build/rules/rules2.html#r3c2 "NSA Official Tournament Rules", National Scrabble Association] , so that overstepping the allotted time by 61 seconds carries a 20-point penalty.

Time trouble

Frequently, players use up a large portion of their time early in the game, and are left with only a few minutes for the final moves. A player with little time is said to be in time trouble, and is forced to play quickly, increasing the probability of making blunders.

Rules governing time trouble in Chess

FIDE has some additional rules regarding players in time trouble.

The first rule regards the recording of moves. A player with less than five minutes remaining, in a game where there is not a 30-second or greater time increment per move, is not required to keep score as usual. However if the player makes the time control, he must update the scoresheet before making a move as soon as the flag falls, marking expiry of the first, and now passed, time control. If only one player is in time trouble and not recording moves, the opponent's scoresheet may be used to update the score. In the case of "mutual" time pressure, where both players have stopped recording the moves, the tournament director or an assistant should be on hand to record the moves as they are played, and their notes can be used to update the scoresheets upon passage of the time control. If the game score is not recorded by anybody during the time pressure period, the players, shall endeavor to reconstruct the moves of the game, under the control of the tournament director, if this is not possible the game continues with the next move being regarded as the first move of the next time control. [ [http://www.fide.com/official/handbook.asp?level=EE101 FIDE Laws of Chess] Articles 8.4 to 8.6]

The second rule regards the arbiter's possibility of ending a game as drawn due to a player's lack of effort in winning the game by "normal means". Occasionally it happens in a sudden death time control without increments that a player has trouble in physically executing an indefinite series of moves in the time remaining. The opponent could try playing on this, and continue to play on in the hopes of winning by time forfeit, rather than by winning the position on the board. To prevent this FIDE has article 10.2 [ [http://www.fide.com/official/handbook.asp?level=EE101 FIDE Laws of Chess] Article 10.2] A player with less than two minutes remaining can, if he considers that the opponent is no longer trying to win the game by normal means, claim a draw and summon the arbiter. The arbiter may accept the claim (which ends the game immediately as a draw), reject the claim (after which the game continues, with the opponent receiving two additional minutes), or postpone the decision. In this case the opponent may be given two minutes extra, and the game continues until the arbiter makes a call or the claimant's flag falls after which the arbiter makes a decision. Decisions made by the arbiter under 10.2 are final.

USCF version

Tournaments governed under the rules of the United States Chess Federation have a similar rule to FIDE's 10.2, called the "insufficient losing chances" rule. A player with less than two minutes remaining without time delay can petition the tournament director for a draw on the grounds that the opponent has no reasonable chance of winning the position, had both players had ample time. In USCF's guidelines, this would mean an average tournament player (class C) having a less than a 10% probability of losing the position against a master, with both players having sufficient time. The tournament director may accept the claim (ending the game as drawn), reject the claim and penalize the claimant with one minute less time, or postpone the decision. If the tournament director postpones the decision, there is the option of substituting a non-delay clock with a delay clock with the claimant having his remaining time halved. Since the insufficient losing chances rules calls upon discretion from the tournament director, clocks with the time delay feature are preferred over clocks without them. [ [http://www.uschess.org/tds/clockrules.php USCF page on clock rules] (Everything You Ever Wanted To Know About The USCF's New Clock Rules, But Were Afraid To Ask)]

Notes and references

External links

*US patent|4884255|US Patent No. 4,884,255 for Fischer's clock
* [http://brainrook.com/archives/54-Time-limit-for-games-on-BrainKing.html Game time controls on BrainKing]
* [http://youtube.com/watch?v=fNQjXHjRkNQ A sudden death time control determines the 2008 U.S. Women's Chess Championship ]