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. For turn-based games such as chess, shogi or go, time controls are typically enforced by means of a game clock, which counts time spent on each player's turn separately. A player that spends more time than the time control allows is penalized, usually by the loss of the game. Time pressure (or time trouble or Zeitnot) is the situation where one player has very little time on their clock to complete their 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. In chess, the categories of short time limits are: "bullet", "blitz", and "rapid". "Bullet" games are the fastest, with either a very short time limit per move (such as ten seconds) or a very short total time (such as one or two minutes). "Blitz" games typically give five to ten minutes per player, and "rapid" games give between ten and sixty minutes. In Go, anything under twenty minutes could be considered "blitz". Methodology The exact approach to using a game clock to regulate games varies considerably. Sudden death This is the simplest methodology. Each player is assigned a fixed amount of time for the whole game. If a player's main time expires, they generally lose the game. 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, often the expiration of the main time. In chess, reaching a fixed number of moves can trigger the gain of a fixed amount of extra time. This usually occurs in long games after the 40th move: e.g. 120 minutes to complete the first 40 moves, and another 30 minutes added to the leftover 120 minutes to complete the rest of the game. 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. In tournament Scrabble, the time control is standardized to 25