Sukaku
A pencilmark-style variant where clues are given as candidate sets
Sukaku is fully playable. Choose a difficulty and start solving.
Sukaku (数角) is a Sudoku variant where instead of given digits, each cell is given a set of possible candidates. The solver must eliminate candidates using standard Sudoku logic until each cell has exactly one remaining candidate. Some Sukaku puzzles provide very sparse candidate sets (near-complete givens), while others provide full or nearly-full candidate lists, requiring advanced techniques to solve.
Like all Sudoku variants, Sukaku builds on the classic 9×9 foundation. Every row, column, and 3×3 box must contain each digit from 1 to 9 exactly once. The variant constraint is added on top of these standard rules, never replacing them.
If you're new to Sudoku, start by learning the basic rules and techniques before attempting variants.
Techniques Useful for This Variant
| Technique | How it applies |
|---|---|
| Pencil Marks / Notes | Essential for tracking candidates alongside the variant constraint |
| Obvious Singles | Cells narrowed to one candidate by the combined constraints |
| Hidden Singles | Digits with only one valid cell in a unit after variant elimination |
| Pairs and Triples | Locked candidates exposed by the additional constraint |