Clone Sudoku
Marked regions must contain identical digit arrangements
Clone Sudoku is fully playable. Choose a difficulty and start solving.
Clone Sudoku marks pairs of regions (clones) on the grid. Each pair of clone regions must contain exactly the same arrangement of digits — if one clone has a 3 in its top-left cell, the other clone must also have a 3 in its corresponding cell. Clone constraints create powerful symmetry-based deductions that can resolve entire regions at once.
Like all Sudoku variants, Clone Sudoku 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 |