Time display

A chessclock has two connected time displays, one for each player, and only one can run at a time. A display shows the remaining time and includes a signal called a flag, which indicates that the allotted period has expired.

The display may be a mechanical dial or a digital screen. Digital clocks can also show seconds, playing periods, increments, which are extra seconds awarded with each move, and a move count recorded by the device. FIDE technical specifications require displays and flag signals to be readable under normal tournament conditions.

In the absence of an evident defect, the indication given by the chessclock is conclusive. If the device is faulty or incorrectly set, the arbiter may stop it, replace it, and determine the times to retain. An external broadcast screen does not replace the official clock and cannot by itself support a claim, a formal request for an arbiter's ruling.

A display is not the whole chessclock. When a player presses the clock, one display stops and the other starts. A talking chess clock provides equivalent information through audio for access without sight.