How to play a nonogram
- Pick a size, or Custom for any size from 5 to 50 squares a side. The numbers beside each row and above each column are its clues: the lengths of the runs of filled squares in that line, in order, with at least one empty square between runs.
- Click a square to fill it. Right-click, or switch Tap to Cross out on a phone, to mark a square you know stays empty. Drag to fill or cross out a whole run at once.
- A clue fades when its line matches. Fill every line correctly and the hidden picture appears.
How to start a nonogram
Start with the biggest clues. In a 10 square row with a clue of 8, the run must cover the middle 6 squares wherever it sits, so fill them. The same works for several runs: a row of 10 with the clue 4 4 needs at least 9 squares, so the run positions barely move and most of both runs can be filled at once.
Next, look at the edges. A filled square in the first column belongs to the first run of its row, so the whole of that run can be filled from the edge. Then cross out anything the runs can’t reach.
Tips for harder puzzles
Cross out as you go: empty squares are as useful as filled ones, because they split a line into shorter gaps that only some runs fit. When a clue fades, its line is finished, so cross out the rest of it and it can’t confuse you later.
The thick lines mark every fifth square, which makes runs of 6 or 7 quick to place. And switch direction often. A square you settle in a row is new information for its column, and every puzzle here is built so there is always a next step somewhere.
About nonograms
Nonograms are picture logic puzzles from Japan, first published in the late 1980s. The name joins Non Ishida, one of the puzzle’s inventors, with the word diagram. The puzzles here are made fresh each time from random pictures, smoothed so they form shapes, and every one is checked so it can be solved without guessing.