GLASS / VARIANT
Skyscraper Sudoku
Buildings of height 1–9. The clue is how many you can see.
Click a cell, then a digit. Arrow keys move, 1–9 place, Backspace clears.
Rules
Think of each digit as the height of a building. A clue outside a row counts how many buildings are visible from that side: a taller building hides everything behind it. A clue of 9 means the row is perfectly sorted; a clue of 1 means the first cell holds the 9.
- The clue counts visible buildings from that direction, not their sum.
- A building is visible only if it is taller than every building before it.
- A clue of 1 means the tallest building stands first.
- A clue of 9 forces the row or column into ascending order from that side.
- Clues are given on the left of each row and above each column.
Good to know
Ordinary sudoku rules still apply underneath the variant: every row, column and 3×3 box holds 1–9 exactly once. The extra rule sits on top and is usually what breaks the puzzle open.
More sudoku
All sudoku variants ↗Or read how to play Sudoku ↗.