We've covered all the special moves in chess as long as you don't consider the chess clock. But clocks are often used to time games, whether in tournaments or in clubs or just to make a game go fast in a friendly game in somebody's home, in a park, or on the Internet.
A chess clock is really two clocks in one housing. When you make a move, press the button on your clock and your clock will stop ticking while your opponent's clock will begin ticking. When your opponent makes his move, your clock will start ticking while his clock stops ticking. That way the entire game can be timed, with each player only being charged for the time it takes to come up with her move.
Chess clocks come in two types. A digital chess clock (sometimes referred to as allegro) is one that displays the exact number of minutes and seconds available for each player. When a player runs out of time using a digital clock, the display will read 00:00. A mechanical clock (sometimes referred to as analog) is one with the traditional clock face and hands. A mechanical clock also has a device called a flag that signals when a player's time has expired. When a player runs short of time using a mechanical clock, the hands of the clock will begin to raise the player's flag. When time expires, the player's flag falls.
Speed or Rapid Chess
Chess players often want to play a great number of games very quickly. There are various reasons for wanting to do this, but we'll just look at how to do it. For that you need a chess clock. You set the clock for five minutes for each player (or seven minutes, three minutes, or thirty minutes or whatever you want) and commence playing.
As long as the players remember to push in the button at the top of their side of the clock, the game will move along until someone plays a checkmate or gets one of various drawn positions. Or until somebody's flag falls. That person has run out of time and automatically loses, just as if he had been checkmated.
A variation on speed play is the bullet chess so popular on the Internet. That usually allows one minute for the game by each player. Of course, you don't use a digital or a mechanical clock for such chess, since the clock is automatic, and your move triggers the change of time from you to your opponent and back again.
Slower Time Limits
Yet another way to use a chess clock is to give each player a set amount of time for a set amount of moves. A very popular time limit used to be forty moves in two hours. In this version of timed chess, the players must keep score of the game if they want to be able to make a claim that their opponent overstepped the time limit. Otherwise, how could anybody know that the forty moves were reached?
New rules have been made to accommodate players who are easily winning the position but have no time to play out the win. These include lack of mating material, insufficient losing chances, and a new device on chess clocks known as time increments. It's all there waiting for you if you should decide to get involved in tournament chess.
In a slower time limit, keeping track of the moves is an essential ingredient. You will learn more about keeping score of a game in the next chapter.