Ten Flat

How to play Ten Flat

Tap Start and the stopwatch starts counting. Your job is to tap Stop at exactly 10.000 seconds. The catch: after three seconds the display goes dark, so the last seven seconds happen in your head.

When you stop, the clock lights up again and shows how far off you were, to the millisecond, early or late. The closer you get, the better your rank:

• Ten flat. Exactly 10.000 seconds.
• Atomic clock under 10 ms off, Metronome under 50 ms, Sharp under 150 ms.
• Close under 400 ms, Ballpark within a second.

The ruler under the clock shows your miss against those rank zones and your last few rounds, and the row below the button keeps your best, your average, your run of sharp stops and how many rounds you've played.

Any round within a second can go on today's board, a daily leaderboard of the closest stops. You play under a random nickname like Brisk Otter (tap the dice for another one), so there's nothing to sign up for. The board resets at midnight UTC.

Controls: tap the big button, or press Space or Enter on a keyboard. Tip: start counting the moment you tap, not when the numbers move, and count "one Mississippi, two Mississippi" out loud if nobody's watching.