Focus timer for deep work
Twenty-five minutes of focus. Five minutes of rest.
Four sessions, then a longer break. Begin again.
Each minute is a dot. Watch them fill.
Just time, and the work in front of you.
Koku (刻) is the Japanese word for a moment of time.
Have a question or found a bug? Reach out and we'll get back to you.
Koku does not collect, store, or transmit any personal data. There are no accounts, no analytics, no tracking, and no network requests. All timer data stays on your device.
That's the whole policy.
Effective date: May 8, 2026