Hyper / Windoku
Four extra shaded 3×3 boxes must each contain 1–9
Hyper / Windoku is fully playable. Choose a difficulty and start solving.
Four shaded 3×3 windows, offset from the standard boxes, each need all nine digits. Window cells answer to up to five houses, so candidate lists shrink fast and easy placements arrive early. Roughly classic difficulty overall, with a denser, more interlocking feel.
For the complete rules, worked examples and solving techniques, read the full How to Play Hyper / Windoku guide.
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 |