Puzzle guide
How to solve Skyscrapers
In Skyscrapers you build a little city. Every row and column holds buildings of different heights, and the numbers around the edge say how many of them you can see from there, because tall buildings hide shorter ones. Here is how to read those numbers.
The rules
- Put a building in every cell. Heights go from 1 up to the number of cells in a row.
- Each height appears once in every row and once in every column.
- A clue on the edge says how many buildings you can see from there. Tall buildings hide shorter ones behind them.
- Not every row or column has a clue on every side. A missing clue says nothing.
A solved puzzle
Your first moves
- Find every 1 on the edge: the tallest building stands right next to it.
- Find every clue equal to the size of the puzzle: that row or column climbs 1, 2, 3, 4 … away from it.
- Next to a big clue, the first cells can only be low buildings. Write those limits as notes.
- Then fill rows and columns like a Sudoku: every height once.
Techniques, step by step
A clue of 1, and a clue of 4
A 1 means you see only one building. That can only happen if the tallest building stands right in front of the clue, hiding all the others. So the first cell is the tallest height, here 4. The opposite clue, equal to the size of the puzzle, means you see every building. That only works if they climb one step at a time: 1, 2, 3, 4.
Low buildings near a big clue
A clue of 3 in a row of four means you must see three buildings. If the first cell were a 4, you would see only one; if it were a 3, you could see at most two. So the first cell is 1 or 2, and the second cell is at most 3. The rule of thumb: the bigger the clue, the lower the buildings near it have to be.
Only one place for a height
Where does the 4 go in the top row? Not in the first cell: the clue 2 says you see two buildings, and a 4 in front would hide everything. Not in the second or third cell, because their columns already have a 4. Only the last cell is left. Asking where a height can go is often faster than asking what a cell can hold.
Count the buildings
The clue 2 at the top of the right column must see exactly two buildings. The 3 at the bottom is already there, so the top two cells hold 1 and 2. Try both: 1, 2, 3 shows three buildings, too many. 2, 1, 3 shows two: the 2, and the 3 behind it. So the top cell is 2. On bigger boards you do the same thing: write the few ways a line can still go, and keep only those that match the clue.
Two clues at once
This row has a 2 on both sides. If the 4 stood at an end, you would see only that one building from that side, not two. So the 4 is in one of the two middle cells, and neither end can be a 4. Two clues on the same row or column work together, and often leave only one way to fill the line.
Common mistakes
- Counting hidden buildings. You only see a building if it is taller than every building in front of it. 2 1 3 shows two buildings, not three.
- Reading a clue from the wrong side. A clue counts from its own side, looking into the grid. The same row can show 1 from the left and 4 from the right.
- Repeating a height. Like in Sudoku, each height is used once per row and once per column.
- Trusting a board with no warnings. The app only checks a line when it is finished, so an empty board has no warnings either. Keep going until every cell has a building.
Questions and answers
Ready to play?
Start at the 1s and the big clues, keep low buildings near big numbers, and count what each clue can see. That is how every city gets built.