What is the online chess clock?

A clock split into two halves, one per player, exactly like a tournament chess clock. Each player taps their side after every move; their clock stops and their opponent's starts.

How to use the chess clock

Pick a time control from the settings gear (5+3 for blitz, 15+10 for rapid, custom for everything else). Place the phone between the two players in portrait orientation. The top half is rotated so it reads upright to the player opposite you. White plays first, so the first tap is on white's side (the bottom half); this stops white's clock and starts black's. Repeat. The reset icon needs a confirmation tap, so an elbow can't end your game.

Why use a chess clock?

Casual chess at home rarely has a physical clock. This is one any phone can run. For Fischer time controls (5+3, 15+10) you would otherwise need a dedicated device or an app install.

Common questions

What is Fischer increment?

After every move, a few seconds are added back to your clock. So in 5+3, you start with 5 minutes and gain 3 seconds per move. Helps prevent the game ending purely on the clock in winning positions.

What happens at 00:00?

You lose on time. The other player wins. A chime plays once and the screen shows who won.

My phone sleeps mid-game. Can I keep the screen on?

The page requests Wake Lock when a game is running, so the screen stays awake as long as your browser supports it (most modern phones do).

Does it work in landscape?

The layout stays portrait. Rotating the device shrinks the two halves but they remain stacked. The intended position is portrait with the phone between players.

What if I switch tabs mid-game?

The active clock pauses (browsers throttle background tabs). When you come back, the clock resumes from where it was. Like holding the pause button on a tournament clock.