Sudoku — medium 2026-10-16
The clock starts when you hit Start — server-timed.
You're not signed in — play free, unofficial and untimed-on-the-board. Your time shows at the end with the rank it would have earned. Sign in first to make it count.
How to play sudoku
- Fill the grid so every row, every column and every 3×3 box holds 1–9 with no repeats.
- Click a cell, then type a digit or tap the number pad under the grid. ⌫ erases. The grey givens are locked.
- Stuck? Hit ✎ notes (or press N) to pencil in candidates — notes don’t count as an answer.
- It checks itself when the grid is full.
How to play sudoku
- Fill the grid so every row, every column and every 3×3 box holds 1–9 with no repeats.
- Click a cell, then type a digit or tap the number pad under the grid. ⌫ erases. The grey givens are locked.
- Stuck? Hit ✎ notes (or press N) to pencil in candidates — notes don’t count as an answer.
- It checks itself when the grid is full.
Three grades of the same daily habit
Every day there are three fresh sudoku here — easy, medium and hard — each generated with a unique solution and graded by the hardest technique it actually requires, not by how many givens got deleted. Easy falls to singles alone; medium expects pointing pairs and box-line work; hard will make you earn it. All three are free, and each grade keeps its own leaderboard.
Notes, checks and the honest clock
Click a cell and type, or use the pad under the grid; hit ✎ notes (or press N) to pencil in candidates — notes never count as answers. The grid checks itself the moment the last cell fills. Your time runs on the server between Start and that final digit, and every rated solve is replayed input by input, with human-pacing checks, before the board believes it — the same gauntlet described in how the honest board works.
Faster without guessing
Open by placing the digits that already appear most often — each placement constrains a row, a column and a box at once. Sweep for naked singles, then work box by box asking where each missing digit can live, not what each cell can hold. On the hard grid, keep your notes ruthless: a stale candidate is a lie you told yourself twenty seconds ago. And never bifurcate — every grid here falls to pure logic, and guess-and-backtrack trains exactly the habit the timer punishes.
All three grades, every past day: the sudoku archive.