Expert Sudoku — Play Free Online
Free expert Sudoku — the hardest level here, at around 24 clues. These grids are built to remove the easy entry points, so expect long stretches with no placement at all, followed by a run of fifteen squares once you find the deduction that opens it.
- Clues to start
- about 24
- Par time
- 25 min
- Cost
- free, no sign-up
Very hard, but never unfair
Every puzzle on this page has exactly one solution, and that solution can always be reached by deduction. The generator stops removing clues the moment another removal would leave a grid with two possible answers, so a position that seems to demand a guess is a position where a deduction is being missed — not a puzzle that needs one.
What makes it expert is reach. The move you need may span two rows and two columns at once, or may only appear after you have cleared away candidates that never get placed themselves. Hidden pairs and the X-Wing are the usual keys, and both are explained in the expert guide.
How to approach one
Fill in complete notes before hunting for anything clever — every technique at this level reads patterns out of the candidate marks, and a partial grid of notes hides exactly the pattern you are looking for. Then work systematically rather than by inspiration: one digit at a time, one unit at a time, in the same order each pass.
Give yourself permission to take two sittings. The par time is 25 minutes and the board saves itself on your own device, so stepping away costs nothing but the speed bonus.
Scoring at this level
Expert carries the largest completion bonus and the steepest speed bonus of the four levels, which is what makes it worth playing for a leaderboard place: a clean expert solve outscores a fast easy one by a wide margin. Mistakes cost 50 points each and hints 75, so a careful slow solve usually beats a quick messy one.
Other levels
- Easy Sudoku — about 42 clues.
- Medium Sudoku — about 34 clues.
- Hard Sudoku — about 28 clues.
- How to play Sudoku — the rules, plus a separate guide for each level.