Evil Sudoku
The toughest grids we offer. Evil Sudoku strips the givens to the bone, so only the advanced techniques will move it — but it is still pure logic with exactly one solution, never a guess. Here is what makes a board evil and the patterns that finally crack it; tap below to take one on.
How to solve an evil Sudoku
- Squeeze out every single and pencil all candidates before anything else.
- Work pairs, triples and pointing pairs to thin the grid as far as it will go.
- Reach for the X-Wing, Swordfish and Y-Wing when the simpler moves stall.
- If still stuck, try simple colouring or a unique-rectangle elimination.
- After every elimination, sweep again for hidden singles — evil grids unlock in long chains.
- Never guess — an evil Sudoku is solvable by logic, so a dead end means a missed deduction.
What makes a Sudoku "evil"?
Evil is the hardest tier: the fewest givens and an arrangement that defeats every simple move, so you must chain advanced techniques to make progress. Nothing about the rules changes — there is no maths and still exactly one solution — but an evil board can demand fish patterns and colouring where expert needed only pairs and wings.
The advanced techniques evil demands
Evil grids call on the whole toolkit: the X-Wing, Swordfish and Y-Wing, plus simple colouring and the unique rectangle. You rarely need all of them on one board, but a stuck evil grid is always waiting for one specific pattern. Build them up on hard and expert first, then come back. Full toolkit: tips & strategy.
Evil vs expert vs hard
The tiers are a ladder of fewer givens and deeper chains: hard needs the odd advanced move, expert needs them regularly, and evil may require fish and colouring to finish. If evil is a grind, it is not a wall — drop a level, drill the techniques, and climb back up.
Evil Sudoku: FAQ
What is evil Sudoku?
Evil is the hardest difficulty tier, with the fewest given numbers and puzzles that require advanced techniques — X-Wings, Swordfish, Y-Wings and colouring — chained together. It is still fully logical with exactly one solution.
Is evil the hardest Sudoku level?
Here, yes — evil sits above expert and hard. Some sites use the word "extreme" or "diabolical" for the same idea: minimal givens and deep chains of advanced techniques.
Can evil Sudoku be solved without guessing?
Yes. Every evil board here is generated and checked to have a single solution reachable by logic alone. If you are stuck, there is an advanced elimination to find — never a need to guess.
How do you get better at evil Sudoku?
Learn the advanced patterns one at a time on hard and expert grids — the X-Wing, Swordfish, Y-Wing, colouring and unique rectangle — until you can spot them quickly, then bring them to evil boards.