Evil sudoku
Play online10,480 evil puzzles · about 28 clues each
Evil sudoku — the hardest puzzles
Our nastiest grids. Even after every standard technique the puzzle stays locked — you will need long chains, Nishio-style reasoning or a brave assumption.
- Free, no sign-up, no ads
- Pencil marks, undo and 3 hints per puzzle
- Your game is saved if you leave and come back
What to expect from evil sudoku
Evil puzzles are the ones Sudoku Explainer cannot finish with its catalogue of human techniques. They still have exactly one solution, but reaching it takes forcing chains, Nishio or careful trial and error. Use your three hints wisely.
New to a technique? Each one is explained step by step, with a diagram and practice puzzles, in the free Sudoku Academy.
Techniques you'll need
All difficulty levels
Evil sudoku FAQ
What is evil sudoku?
Evil sudoku is the hardest level on Sudoku Corner: puzzles that standard human techniques cannot finish. They have a unique solution, but you will need forcing chains, Nishio or trial and error to find it.
Is evil sudoku harder than expert?
Yes. Expert puzzles are tough but always yield to logical techniques. Evil puzzles go beyond them.
Is guessing allowed in evil sudoku?
Nothing stops you, and some solvers do. A cleaner approach is Nishio or a forcing chain: assume a candidate, follow the consequences and remove it if it leads to a contradiction.
How long does an evil sudoku take?
Anything from 45 minutes to several sittings. Your game is saved in your browser, so you can come back to it later.
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