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Evil Sudoku

Evil Sudoku represents the most diabolical challenge in the puzzle world. These grids push the boundaries of logic with the fewest possible givens. If you have conquered expert level and still crave more, evil Sudoku is your next frontier.

Evil puzzles require mastery of every technique: X-wing, swordfish, naked and hidden triples, box/line reduction, and multi-step chain logic. There are long stretches where progress seems impossible — then a single elimination cascades through the grid.

The key to evil Sudoku is patience and meticulous note management. Every candidate matters. A single missed elimination can leave you stuck for minutes. But when you finally crack an evil puzzle through pure logic, the rush is worth every minute of effort.

Evil Sudoku Tips

Maintain perfect pencil marks

In evil puzzles, every candidate elimination counts. Double-check your notes after each placement. One overlooked candidate can block your progress entirely.

Look for swordfish patterns

Swordfish extends X-wing to three rows and columns. When a digit appears as a candidate in two or three cells in each of three rows, you can eliminate it from other cells in the involved columns.

FAQ

What is evil Sudoku?

Evil Sudoku is the hardest difficulty level, featuring puzzles with very few givens that require advanced techniques like X-wing, swordfish, and chain logic to solve.

What is the hardest type of Sudoku?

Evil Sudoku is considered the hardest standard difficulty. These puzzles require mastery of all advanced techniques and can take experienced solvers 30 minutes or more.

Try Other Difficulty Levels

Easy Sudoku Medium Sudoku Hard Sudoku Expert Sudoku