Skyscrapers is a logic puzzle on a square grid. Think of the grid as a small city seen from above: every cell holds a tower, and the number in the cell is its height. Around the edge stand the clues. Each clue tells you how many towers a person standing at that spot can see when looking along the row or column — taller towers hide the shorter ones behind them. Every puzzle here has exactly one solution and can be solved by reasoning alone.
How to play
- On an N × N grid, every height from 1 up to N turns up exactly once in each row and once in each column.
- An edge clue gives the number of towers visible from that side. A tower is visible when it is taller than every tower in front of it.
- Edges without a number give no information. Some puzzles also start with a few towers already in place.
- Tap a cell and choose a height from the number pad, or type it on your keyboard. Switch on pencil mode to keep small notes of the heights a cell could still take.
Clashing heights in a row or column are highlighted, and the undo button walks back as many steps as you need. The puzzle is solved when every cell is filled and every clue is satisfied.
Techniques
- A clue of 1 means the tallest tower, N, stands right next to that clue: nothing can be in front of it.
- A clue of N means you see every tower, so the heights rise by one at each step, starting with 1 at that edge.
- Distance limits. Count cells from the edge, the first being 1: next to a clue c, cell number d holds no more than N − c + d. On a 5 × 5 grid with a clue of 4, the first cell is at most 2.
- Opposite clues. The tallest tower is visible from both ends, so two opposite clues add up to at most N + 1. When they add up to exactly N + 1, the tallest tower's position is fixed.
- Where can N go? Each row and column has exactly one tallest tower. Ruling out cells next to clues of 2 or more often leaves only one place for it — and once the tallest towers are placed, the next tallest come quickly.
- Notes pay off on larger grids. On a 6 × 6 grid, write candidates in pencil after the first deductions and look for a height that fits only one cell of a row.
There is more on clue reading, with worked examples, in the guide reading skyscraper clues.
Sizes
This page offers 4 × 4 up to 7 × 7 grids. In the daily set the grid is 4 × 4 on Monday and Tuesday, 5 × 5 from Wednesday to Friday and 6 × 6 at the weekend — small enough for a coffee, big enough to need a plan.
Questions
Is guessing ever needed?
Never. Each grid is generated together with a logical solver that reaches the end one forced step at a time, so the solution can always be found by reasoning.
What does the hint do?
It shows a cell whose height can be worked out from the current position. If there is a mistake on the board, it points to that cell first.
Can a clue be 0 or missing?
A missing clue simply gives no information. There are no clues of 0: from every edge at least one tower is visible.
Is my game saved?
Yes, automatically, with the full undo history. Reload and carry on.