Evil Sudoku
The fewest givens we generate. Long, stubborn, and not a warm-up.
Puzzle 1
24 clues · 9×9
Puzzle 2
24 clues · 9×9
Puzzle 3
24 clues · 9×9
Puzzle 4
24 clues · 9×9
Puzzle 5
24 clues · 9×9
Puzzle 6
24 clues · 9×9
Puzzle 7
24 clues · 9×9
Puzzle 8
24 clues · 9×9
About evil sudoku
Evil is the thinnest set we generate, 24 givens against 57 empty cells. These take most solvers well past twenty minutes, and there is no shortcut around the opening.
Every cell you place has to be earned by elimination. Work in candidates from the first move, be careful about writing them accurately, and never guess: a wrong guess on a grid this sparse stays invisible for another twenty cells, by which point the whole thing is ruined and you cannot tell where it went wrong.
Frequently asked questions
How hard is evil sudoku?
It is the thinnest set we generate: 24 givens against 57 empty cells. Most solvers spend well over twenty minutes, and the opening in particular has no shortcut.
Is an evil sudoku still solvable by logic?
Yes, and this matters. Every puzzle here has exactly one solution reachable without guessing. A grid this sparse punishes a wrong guess brutally, since the contradiction may not surface for another twenty cells.
What technique do I need for evil sudoku?
Full candidate notation from the first move, then systematic elimination: naked and hidden pairs, and candidates confined to one line inside a box. Accuracy in writing the candidates matters as much as spotting the patterns.
What if evil is too much?
Drop to expert, which starts from 26 givens and usually offers one or two early footholds. It is a real step down without being easy.