To solve a nonogram, find the cells a clue forces no matter where its block sits, fill those first, mark the certain blanks with an X, and then cross-reference each row against its columns so one line confirms the next. Every puzzle has a single solution you can reach by logic, never by guessing. You can work through one on the live Nonogram board.
Read the clues
The numbers beside a row or above a column give the lengths of the filled blocks in that line, in order, with at least one empty cell between blocks. A clue of 4 1 on a row means a run of four filled cells, then a gap, then a single filled cell, somewhere along the row. A line marked 0 has no filled cells at all, so the whole line is blank.
Your task is to work out, for every cell, whether it is filled or empty, using the row clue and the column clue that meet there.
Find the forced cells first
The fastest way in is to look for lines where the clue barely fits. Take a row of ten cells with a clue of 8. The block of eight can only sit so far left or so far right, and wherever it lands, the middle cells are filled in both positions. Those overlapping cells are forced, so you can fill them straight away.
The same overlap trick works for any large clue relative to its line length. Fill the forced cells in the most constrained rows and columns, and you build a skeleton the rest of the puzzle hangs on.
Mark blanks and cross-reference
Filling cells is only half the method. Marking blanks with an X is just as powerful. Once a row clue is fully satisfied, every other cell in that row is blank, so mark them. An X in one line frequently forces a filled cell in the column that crosses it, which forces another row, and so on.
A short checklist keeps you moving:
- After filling any block, X out the cells that cannot be part of any remaining run.
- When a line’s clues are all placed, X the rest of the line.
- Whenever a row gives you a new cell, check the column through it for a fresh deduction.
Because there is always one solution, progress is steady rather than lucky. Open the Nonogram board, start small, and watch the picture appear, and for why deduction puzzles are good practice, see the benefits of puzzle games.