Solve nonograms with logic, not guessing

Row clues like '3 1' mean a run of 3, a gap, a run of 1. Cross the rows against the columns and the picture fills itself.

Tools used in this guide

The job

Each row and column carries clues — the lengths of filled runs in order. '4 2' on a 10-wide row means a block of 4, at least one blank, a block of 2. The grid is a bitmap waiting to be discovered; the clues are its compression.

Fill, mark, cross

Click to fill, right-click (or the mark toggle) to X-out cells you know are empty. Rows that satisfy their clues highlight. Generated puzzles are checked for a unique solution — every puzzle is solvable by logic alone.

Start with the extremes: a clue summing to the row length fills it completely ('10' on a 10-row), and '0' X's it all.
Edge-anchored runs are the other freebie: a '3' clue with a filled cell at the edge pins the run's position.

Sizes and solver

Puzzles generate up to 15×15. Stuck? The hint applies a line deduction the solver found — the same propagation engine that proves uniqueness, capped at 200,000 search nodes so the page never hangs.