How to solve a nonogram

A nonogram (also called a picture logic puzzle or paint-by-numbers grid) hides a picture in a grid. The numbers tell you which squares to fill.

The rules

• The numbers to the left of a row give the lengths of the runs of filled squares in that row, in order from left to right.
• The numbers above a column do the same, from top to bottom.
• Between two runs there is at least one empty square. A clue of 3 1 means three filled squares, a gap, then one filled square.
• A clue of 0 means the whole line is empty.

A small example

Tips

• Start with big numbers. In a row of 10 squares, a clue of 8 must cover the middle 6 squares wherever the run starts.
• Add the clues of a line plus one gap between each pair. If the total is close to the line length, many squares are already fixed.
• Mark squares you know are empty with a dot. That helps as much as filling squares in.
• Work back and forth between rows and columns: every square you settle gives new information to the line that crosses it.
• Use a pencil. The thick lines every five squares help you keep your place.

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