This is a chess clock for two people sharing one screen. Put the phone down next to a real board, pick a time, and it does what the wooden clock with two dials does: it keeps each player's time separately and only ever runs one of them.
The clock above is already set to five minutes each, and the first tap on either half starts the game. The screen splits down the middle, one half per player. Held upright, the far half is drawn upside down so the person across the table reads their own time the right way up; turned sideways, the two halves sit next to each other instead.
A chess clock is two clocks in one case, and only one of them ever runs. Yours counts down while you think. You make your move on the board, then press your own side, which stops your clock and starts your opponent's. It comes back to you when they press. What it measures is the time each of you spends deciding, not how long the game takes.
If your clock reaches zero you lose, even in a position you were winning. Players call it flagging, after the flag an old mechanical clock pushed up. One exception: if the player who still has time could not possibly checkmate you with the pieces left, a bare king being the clearest case, the game is a draw instead. Here the clock that hits zero shows a flag and the other clock stops.
Set the device down between you, alongside the board, with one half facing each player. Pick a time: the presets run from 1 to 60 minutes, and the custom box takes any other number of minutes. Pick an increment too if you want one, from 0 up to 10 seconds.
Black taps first: by convention the player with the black pieces starts white's clock, since white moves first. Any first tap starts the game, so it can be whoever is moving second. After that it is the same every turn: move the piece, then tap your own half. Your clock stops and theirs starts. Pause if you are interrupted, and Resume picks up where you stopped. Reset clears both clocks for a new game, and part-way through a game it asks for a second tap first, so a stray touch cannot wipe what you were playing.
Under twenty seconds the running clock shows tenths of a second and changes to the alarm colour. There is a soft click on each switch and a sound when a clock runs out; the mute button silences both and remembers that next time. On a keyboard, Space switches, P pauses and R resets. While the clock runs it asks the browser to keep the screen awake, so it should not dim mid-game where that is supported. Your last time control is saved on the device.
Increment is time added to your clock each time you move, written after the minutes with a plus sign. So 5+3 means five minutes each, plus three seconds added to your own clock after every move you make. Move quickly enough and your time can go up instead of down. This clock offers 0, 1, 2, 3, 5 or 10 seconds.
The reason to use it is what happens without it: two players who thought hard earlier reach the last few moves with four seconds each, and the finish becomes a scramble decided by who can tap faster. Two or three seconds a move keeps the ending playable. This style is called Fischer increment, after the player who argued for it. Delay, where your clock waits a few seconds before counting down, and Bronstein delay, which hands back only the time you used, are not offered here.
| Time control | What playing it is like |
|---|---|
| Bullet, 1 to 2 minutes | Barely time to think. Fun once in a while, hard to play well. |
| Blitz, 3 to 5 minutes | Quick games, several in a sitting. You see the idea but not the details. |
| Rapid, 10 to 15 minutes | Room to work out a plan and still finish inside half an hour. |
| Classical, 30 minutes or more | One long game. Closest to how tournaments are played. |
If neither of you has played with a clock before, set 10+5 and play one game. Ten minutes each is enough that nobody feels rushed, and the five-second increment keeps the ending sane. You will know after a game whether you want more time or less.
There are two ways to play chess on a screen on this site. 2 player chess offline is one board passed between two people, and play chess online with a friend is the same board over a shared link. Neither has a clock, on purpose: those games are meant to be relaxed, and a clock changes the feel of a game more than anything else you can add.
So this page stands on its own: it does not connect to those games and cannot time them. It is for when the board is real and the only screen on the table is the phone beside it. If a rule comes up mid-game, the rules of chess is one page away, and since a clock is often what gets people writing their moves down, how to read chess notation covers the shorthand.
Yes. There is nothing to buy, nothing to sign up for, and no app to install. Open the page and it works.
Yes, after the first load. Once the page has been open once on that device it keeps working with the connection off, which is handy in a cafe or on a train.
It tries to. While the clock is running it asks the browser to keep the screen awake, and most current browsers allow that. On one that does not, set your screen timeout a little longer before you start.
That clock shows a flag and the other one stops, so the time on both sides stays as it was. Under the rules the player who ran out loses, unless the other player has no way to checkmate with the pieces they have left, in which case the game is a draw.
Yes. The presets cover 1 to 60 minutes, and the custom box takes any number of minutes you type in. Increment is set separately, at 0, 1, 2, 3, 5 or 10 seconds.
Five minutes on each clock to start, and three seconds added to your clock after every move you make. The first number is the starting time in minutes, the second is the increment in seconds.
Yes. It is a turn timer, so it suits any two-player game where players take turns: Scrabble, Go, draughts, backgammon. Nothing about it is specific to chess except the name.
Because the person reading it is sitting opposite you. With the phone flat on the table between you, turning the far half around means you each read your own time the right way up. Turn the device sideways and the halves sit side by side instead.
When there is no board in the room, the same two people can play here. 2 player chess offline passes one device back and forth, and play chess online with a friend sends a link to someone else's screen.