Skyscraper Sudoku
Outside clues show how many 'buildings' are visible from that edge
Skyscraper Sudoku is fully playable. Choose a difficulty and start solving.
Skyscraper Sudoku imagines each digit as a building of that height. Clues outside the grid indicate how many buildings you can see looking from that edge inward — a taller building blocks all shorter buildings behind it. A clue of 1 means the first building must be a 9. A clue of 9 means the buildings are arranged in strictly increasing order (1,2,3,4,5,6,7,8,9). This variant requires both Sudoku logic and permutation reasoning.
Like all Sudoku variants, Skyscraper 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 |