What is the skyscrapers puzzle?
The skyscrapers puzzle is a number grid where every number is a building. A 1 is a short tower and the largest number is the tallest. Each row and column holds every height once, and the clues around the edge tell you how many buildings you would see standing at that spot and looking along the row. Tall towers block the view of shorter ones behind them.
It plays like sudoku with a skyline. Play the skyscrapers puzzle online free here, from 4×4 starters to tough 6×6 boards on four levels.
Where Skyscrapers comes from
The skyscraper puzzle is a regular in puzzle books and puzzle competitions, and it also goes by the name Towers. Who invented it isn’t clearly known. The grid itself is a Latin square, the same structure that sits under sudoku, futoshiki and calcudoku.
How to play here
Pick a size and level on the start card, then press Play. Click or tap a square and type a digit, or use the number pad on a phone, to build a tower of that height. To remove a tower, select the square and press Space, or use Undo. For pencil marks, right-click a square and type digits with a mouse, or turn on Mark in the dock on a phone. Tap an edge clue to grey it out once you have dealt with it.
Undo, Redo and New puzzle are in the dock. The pause menu has Restart, Solve and Enter game ID.
How the clues work
Imagine standing at a clue and looking into the row. You can see the first tower. After that, you see each tower only if it is taller than every tower in front of it.
For example, on a 5×5 grid the row 2, 5, 1, 3, 4 shows two towers from the left (the 2 and the 5) and two from the right (the 4 and the 5). The row 1, 2, 3, 4, 5 shows five from the left and only one from the right.
A step-by-step way to solve
- Place every forced tallest tower. A 1 clue puts the N right beside it.
- Fill rows with a clue of N. They are completely fixed, rising from the clue.
- Rule out tall towers near high clues. A clue of 4 on a 5×5 grid means the 5 can’t be in the first three squares from that side.
- Use pencil marks. List what each square could hold and cross numbers off as rows and columns fill.
- Finish with sudoku logic. When a height has only one possible square left in a row or column, place it.
Why play Skyscrapers?
If you like sudoku but want something with a different picture in your head, skyscrapers is a great next step. The grids are small, so a solve takes a few minutes, but the higher levels ask for real reasoning. Try Futoshiki or Calcudoku for more Latin-square puzzles.
How to play Skyscrapers
- On an N×N grid, build a tower on every square, with heights from 1 to N.
- Every row and every column contains each height exactly once, like sudoku.
- A clue outside the grid says how many towers you can see looking in from that side. Taller towers hide shorter ones behind them.
- A clue of 1 means the tallest tower stands first in line. A clue of N means the heights rise one by one, from 1 to N.
- On harder boards some towers are given, and some edge clues are missing.
Skyscrapers tips
Start with the 1s and the Ns
A 1 puts the tallest tower right next to the clue. On a 5×5 grid, a 5 fills the whole row as 1, 2, 3, 4, 5 from that side.
Place the tallest towers early
The tallest tower is seen from everywhere and hides everything behind it. Work out where each N goes in every row and column first.
Read clues in pairs
Clues at both ends of a row can add up to at most N + 1. A 3 facing a 3 on a 5×5 grid puts the 5 exactly in the middle.
Frequently asked questions
What is the trick to skyscraper puzzles?
Treat the tallest tower as the key. A clue of 1 fixes it next to the clue, and a high clue pushes it far away. Once each row's tallest tower is placed, the smaller clues become much easier to read.
Is the skyscrapers puzzle the same as a towers puzzle?
Yes. It's the same puzzle under different names. Skyscrapers is the most common one, and some apps call it Towers.
Does every skyscraper puzzle have one solution?
Yes. Every board here has exactly one answer. The top Unreasonable level may need some trial and error, but the lower levels can always be solved by pure logic.
