The Sudoku Daily Challenge
One puzzle a day, seeded from the date itself — so the grid you get today is the grid everyone else gets today, on every device, this year and next.
The same grid for everyone
There is no server handing out puzzles. The daily is generated on your own device from a seed that is the calendar date, which means two people on opposite sides of the world get bit-for-bit the same grid without either of them being online. It also means the puzzle is stable: reload the page, come back after lunch, or open it on your phone instead — same grid, and your progress on it is right where you left it.
It gets harder as you do
The grade of the daily rises with your own history rather than the calendar, which is the whole point of a daily as an on-ramp. Nobody is dropped into an expert grid on day one, and nobody is stuck on easy for a month either.
| Dailies solved | Grade | What changes |
|---|---|---|
| 0–4 | Easy | Learning where to look. Everything is findable one unit at a time. |
| 5–14 | Medium | Hidden singles and locked candidates. Notes start to matter. |
| 15–29 | Hard | Pairs, triples and the occasional X-wing. |
| 30 and up | Expert | The floor of unique solvability. Long chains, full notes. |
Streaks
Solve today's and your streak grows by one. Miss a day and it starts again from one on the next solve — that is what makes it worth anything. Your longest streak is kept separately, so a broken run does not erase the best you have done.
A daily counts once. Solving it a second time changes nothing, and a run you start before midnight and finish after it still counts towards the day you started, which is where you would expect it.
Where the streak lives. In your browser's own storage, on the device you played on. There is no account, so a streak does not follow you between a laptop and a phone — and clearing site data for this domain clears it. The mobile app keeps its own.
If you lose today's
Three wrong digits ends a run. Today's daily can be restarted as itself for as long as it is today — the seed has not changed, so it is the same grid, and a lost run is not a lost day. Once you have solved it, Play Again hands you a fresh puzzle at the same grade instead, because the daily is done.
Before you start
If a daily at your current grade is proving stubborn, the strategy guide walks through the exact techniques each grade expects, and the rules page covers why guessing is never necessary.