Hyper / Windoku
Four extra shaded 3×3 boxes must each contain 1–9
Hyper / Windoku is fully playable. Choose a difficulty and start solving.
Hyper Sudoku (also called Windoku) adds four extra shaded 3×3 regions to the standard grid. These regions overlap with the normal boxes and must each contain every digit 1–9, just like the standard boxes. The extra constraint can dramatically reduce candidate counts and often makes puzzles easier than they first appear.
Like all Sudoku variants, Hyper / Windoku 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 |