Nonogram Rules, No Nonsense
Each number beside a row or column tells you how many squares to fill in that line. Get them all right and a picture appears. That's it. No maths, no guessing.
The grid and the clues
You get a grid of squares. Rows have numbers on the left. Columns have numbers on top. Every square ends up either filled or empty, and the clues decide which.
What a number actually means
One number, one run of filled squares.
- 3 means three filled squares in a row. Nothing else in that line.
- 1 1 means two single squares, with at least one empty square between them.
- 2 3 means a block of two, then a gap, then a block of three.
Order matters. 3 1 and 1 3 are different lines.
The gap rule (this is the one people miss)
Two blocks in the same line always have at least one empty square between them. The gap can be bigger than one, but never zero.
Example: a ten-square row with the clue 4 4. The two blocks plus the gap between them need at least nine squares. That leaves only one square of slack, so the row is easy to pin down.
What a 0 means
A clue of 0 means the whole line is empty. Mark every square in it and move on.
A full 5×5 example, step by step
Say one row is five squares wide with the clue 5. A block of five only fits one way: the whole row is filled.
Now a column, five squares tall, with the clue 3. The block can start at square 1, 2, or 3. In every case the middle square is covered, so that square is filled for sure.
Next, a row with the clue 1 1 where you already know the middle square is empty. The two single blocks have to sit on opposite sides of it. Done.
Keep doing that, fill what must be filled, mark what must be empty, then re-check the lines that cross whatever you just changed. Most 5×5 puzzles fall apart this way in under a minute.
Use two marks, not one
Fill squares make the picture. Empty squares, marked with an X, are everything you've proved can't be filled.
Mark your empties. Every X you write down removes a possibility permanently. Skip this and you'll keep re-reading the same dead end.
Four mistakes to dodge
- Reading 1 1 as two squares touching. They're separate blocks.
- Thinking the gap is exactly one square. It can be wider.
- Assuming the first block has to start at the edge. It can start anywhere it fits.
- Reading rows and forgetting the columns that cross them.
Quick answers
Do I need to be good at maths?
No. You count and you reason. There's no arithmetic.
What if two answers fit the clues?
Then the puzzle is badly made. Ours are generated to have exactly one answer.
Can I just guess?
You can, but you shouldn't need to. If you're stuck, you've usually missed something. Go back and re-read a line you think you've finished.
What size should I start with?
5×5. It teaches the reading habits, and a puzzle takes well under a minute.
Go try it
The rules take two minutes to read, but the logic only clicks once you solve your first grid. Play a free 5×5 Nonogram
New here? Start with what a Nonogram is, then how to read the clues and the overlap method. When 5×5 feels easy, move up to 10×10.