Play expert Sudoku online
Very sparse. Long chains, and notes close to essential.
Already have a game running at this grade? The same link picks it back up where you left it.
What a expert grid is like
Expert is the floor of what still has exactly one solution: 22 to 27 clues, and grids the solver's whole technique ladder cannot finish without trial and backtracking. Every one is still uniquely solvable — that is checked before the puzzle is ever shown — but you will be holding several chains of reasoning at once, and filling the notes in properly is less a convenience than the only sane way through.
| Clues kept | 22–27 of 81 |
|---|---|
| Hardest technique needed | Beyond the technique ladder |
| Hints per game | 3 |
| Mistakes allowed | 3 |
| Solutions | Exactly one, always |
A grade is two constraints, checked together. Clue count alone is a poor signal — a 30-clue grid can be trivial — so the generator also solves every candidate puzzle with a technique ladder and re-digs anything that comes out easier or harder than this grade promises.
How to approach it
Expect long stretches with nothing to place. Complete notes are not optional here; neither is the discipline of re-checking a unit after every elimination, because on a grid this sparse one removal usually unlocks the next.
You will meet positions the standard technique ladder cannot finish. The grid is still uniquely solvable — that is checked before it is ever shown — so a careful chain will get there. If you take a speculative path, note where you branched: three mistakes is not a generous budget.
Try another grade
- Easy Sudoku — Plenty of clues, and every square findable on its own.
- Medium Sudoku — Fewer clues, and units you have to read as a whole.
- Hard Sudoku — Sparse. Expect to rule things out before anything falls.
- Daily Challenge — one puzzle a day, the same grid for everyone.
New to the game? How to play covers the first few moves, the rules explain why there is always exactly one answer, and the strategy guide works through every technique named above.