How to play Nonogram

What the numbers mean

Each number is the length of one unbroken group of filled squares in that row or column, listed in the order the groups appear. Two numbers, such as 1 1, mean two separate groups with at least one empty square between them. A single 5 on a 5×5 line fills every square in that line.

A worked 5×5 lesson

This walkthrough uses column clues 2, 4, 4, 4, 2 and row clues 1 1, 5, 5, 3, 1 — the same grid as the interactive lesson on this page.

Step 1 — Read a full row. The second row is a 5 on a five-wide grid, so every square in that row is filled. Always start with the line whose clues leave the least slack.

Step 2 — Close a finished group. The first column’s clue is 2, and those two filled squares are already in place, so the rest of that column cannot be filled. Mark those squares with crosses. Crosses are not filled cells; they protect gaps you have proved.

Step 3 — Combine both directions. Row 1 needs two separate groups of 1. Both filled squares are already known from the columns, so its remaining open squares must stay empty. Every confident mark gives the crossing clues less room to move.

Mark what cannot be filled

Use crosses to rule out squares. They do not count as filled cells, but they make the remaining spaces easier to measure. Avoid guessing: every puzzle here has one verified solution.

A line's leftover space is its slack

Add the lengths of the groups, then add one empty square between each pair of groups. Subtract that total from the line length. The remainder is how far the groups can slide. When the remainder is 0, the line is completely determined. When it is small, some squares are filled in every possible placement — those are the squares to mark first, before you look anywhere else.