How to Solve Nonograms (Picross): A Beginner's Guide

Nonograms — you may know them as Picross, griddlers, or 'paint by numbers' puzzles — look cryptic at first: a grid, and rows of numbers around the edges. But there's no guessing involved. It's pure logic, and once a few techniques click, watching a hidden picture emerge one square at a time is genuinely addictive. Here's how to solve them from scratch.

How the clues work

The numbers beside each row and above each column describe the filled squares in that line. Each number is a 'run' of consecutive filled squares, listed in order, and there must be at least one empty square between runs.

• A clue of '5' on a 5-wide row means the whole row is filled.
• A clue of '2 1' means: a run of two filled squares, then a gap, then one filled square — in that order.
• The gaps between runs can be any size (one or more), but the runs themselves are exact.

Technique 1: Fill the full lines first

Look for any row or column whose clue forces the whole line. On a 10-wide row, a clue of '10' fills every square. A clue of '4 5' also fills the whole line: 4 + gap + 5 = 10, so there's exactly one way it fits. Completed lines give you footholds for the crossing lines.

Technique 2: Overlapping

This is the key beginner move. When a run is long relative to the space, the middle squares must be filled no matter where the run sits. On a 10-wide row with a single clue of '8', slide the run to the far left, then the far right — the squares that are filled in both positions (the overlap) are always filled. An 8-run in a 10 space guarantees the middle 6 squares. Mark those, and the rest of the line often follows.

Technique 3: Mark the empty squares

Solving is as much about ruling squares out as filling them in. When you know a square can't be filled — for example, a completed run means the squares on either side must be blank — mark it with an X. Those X's constrain the crossing lines and prevent mistakes. Good solvers X-out at least as often as they fill.

A simple solving loop

• Fill any line the clue completely forces.
• Use overlapping on the longest runs to place guaranteed squares.
• After completing a run, X-out the squares that must be empty around it.
• Switch between rows and columns — each filled square is a new clue for the crossing line.
• Repeat until the picture is complete. Never guess; look for the most constrained line.

Try one now

The best way to learn is to solve a small one. Our free nonogram generator makes 5×5, 10×10 and 15×15 puzzles, each guaranteed solvable by logic with a single unique solution. Play in your browser — click to fill, click again to mark an X — or print a clean PDF with the clues and a solution page. Start on 5×5, lean on overlapping, and you'll be revealing pictures in no time.