Page "Game clock" Paragraph 16

* Hour Glass — a player loses in this time control when he allows the difference between both clocks to reach the specified total amount.

For example, if the total is defined as one minute, both players start their clocks at thirty seconds.

Every second the first player uses to think in his moves is subtracted from his clock and added to his opponent's clock.

If he uses thirty seconds to move, the difference between the clocks reaches one minute, and the time flag falls to indicate that he loses by time.

If he has used twenty nine seconds and then pushes the clock's button, he has one second left on his clock and his opponent has fifty-nine seconds.