The time control (or time limit) is the amount of time available to each player for completing a specified number of moves. Time controls are always used in formal tournaments and matches. A player who fails to make the required number of moves in the time allowed loses the game on time forfeit.
Some popular controls are 40/2, meaning that each player must make 40 moves in 2 hours, and Game/30, meaning that each player has 30 minutes for the entire game. After the initial time control, secondary time controls regulate the next portion of the game.
If the first time control is 40/2, as in our first example, the second time control might be 20/1, meaning that each player has an additional hour to reach move 60. The time is cumulative for each control; a player who has 30 minutes remaining on the clock after the first 40 moves, would have 1 hour and 30 minutes for the second 20 moves.
