Expert Sudoku
The hardest setting — grids stripped down to the bare minimum of given numbers.
How to play
- Fill the grid so every row, column and 3×3 box contains 1 to 9, with no repeats.
- Turn on Notes first — at this level pencil marks are not an aid, they are the method.
- Repeated numbers are highlighted gently and nothing ever ends the run, so you can explore and erase freely.
- The Hint covers the simple steps only; past that, patiently narrowing candidates is the way through.
What it trains
- The hardest grids we generate — fewest givens, longest deductions
- Exactly one solution in every puzzle, verified as it is generated
- No ads, no account and no clock — an extreme grid can sit for days with nothing counting against you
Free expert sudoku online, for people who find hard puzzles go too quickly: each 9×9 grid is carved down to roughly two dozen given numbers, and every one of them still has exactly one solution. Expect to live in pencil marks — straightforward scanning will not carry you far, and the teaching hint only covers the simpler steps, so most of the deduction here is yours. No ads, no account and no sign-up, and no timer and no game over: an extreme grid can stay open for days with nothing counting against you. Plays on phone, tablet or computer.
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