Press the clock

To press the clock is to operate your side of the chessclock after moving. This stops your own time and starts your opponent's. The interval between releasing the piece and pressing the clock still counts against the mover's allotted time.

In ordinary competitive play, pressing the clock completes the move. The board move comes first, followed by the press, and the same hand must perform both actions under the one-hand rule. A player may not press before moving, keep a finger on the clock, hover over it, or strike the device forcefully.

Some moves end the game immediately, such as checkmate, which leaves the king attacked with no legal reply, so no later clock press is needed for them to take effect. By contrast, an illegal move is considered completed once the player presses the clock; this may require position reinstatement, meaning a return to the last identifiable state before the error, as well as a penalty.

Pressing one side is not the same as pausing the entire chessclock. Stopping both displays is reserved for permitted situations, such as seeking the arbiter's assistance.