How to Solve Nonograms
This guide teaches you everything you need to solve a nonogram from a blank grid: how to read the number clues, the core logic techniques that crack every line, and the mistakes that trip up most beginners. Read it once and you'll be able to apply the same handful of ideas to a 5×5 warm-up or a full 15×15 daily puzzle.
What is a nonogram?
A nonogram (also known as a griddler or Picross) is a logic puzzle played on a grid of squares. Every row and column has a set of numbers next to it — the clues. Your job is to fill in the correct cells so that each line's runs of filled cells match its clues exactly. Get every line right, and the filled cells together reveal a hidden picture.
Basic rules
- •Each cell ends up in one of two states: filled or empty.
- •A clue is a sequence of numbers — one number per run of consecutive filled cells in that line, listed in order.
- •Two runs in the same line are always separated by at least one empty cell.
- •A properly designed puzzle has exactly one valid solution — there's always a next logical step, even if it isn't obvious yet.
How to read row and column clues
A clue of "3 1" on a row means: reading left to right, there's a run of exactly 3 filled cells, then a gap of at least one empty cell, then a run of exactly 1 filled cell. Nothing else is filled in that row. Column clues work the same way, just read top to bottom.
Reading a clue
One valid placement of clue "3 1" in a 5-cell line: a run of 3, a gap, then a run of 1.
Complete lines
Two clue shapes resolve a line completely, with no ambiguity at all:
A 0 clue empties the whole line
Clue "0" means nothing is filled anywhere in this line — mark every cell empty.
A clue equal to the line's length fills it completely
Clue "5" on a 5-cell row leaves no room for anything but filled cells.
Overlap method
When a single run's clue is close to the line's total length, some cells are filled no matter where the run ends up sliding. Those guaranteed cells sit in the middle, where every possible placement overlaps. This is usually the very first foothold in a fresh puzzle.
Clue "3" on a 5-cell line
A run of 3 can start at position 1, 2, or 3 in a 5-cell line — but the middle cell is filled in every one of those placements, so you can fill it in immediately without knowing the exact position yet.
Marking empty cells
Solving isn't only about filling cells in — marking cells you're certain are empty (with an ✕) is just as valuable. It rules out placements for the runs that are still undecided and often forces the next fill.
Clue "2 2" on a 5-cell line has only one placement
Two runs of 2 plus the required gap between them already add up to the full line length (2 + 1 + 2 = 5), so there's no room to slide — this placement is the only one possible, and the middle cell can be marked empty with confidence.
Out-of-range cells
Once you know roughly where a run must sit, any cell outside every remaining possible placement for that run can be marked empty — even if you don't know the run's exact position yet. This "eliminate the impossible" thinking, applied line by line, is what turns a handful of overlap deductions into a fully solved grid.
Completed blocks
When a run of filled cells already matches its clue's length exactly, that run is done — it can't grow any further. Both cells immediately next to it must be empty, since a longer run would no longer match the clue.
A finished run of 2 gets empty neighbours
The run of 2 is already complete, so the cells directly beside it are marked empty — they can't belong to this run without breaking the clue.
Common beginner mistakes
- •Filling cells without marking the empty ones — this throws away half the information you've already worked out.
- •Guessing when stuck, instead of re-scanning every row and column for a line that's now closer to complete after your last move.
- •Only checking rows, or only columns — the two always work together. A fill in a row often completes a column, and vice versa.
- •Forgetting that a clue like "1 1 1" needs at least one empty cell between every pair of runs, not just somewhere in the line.
Try an easy puzzle
The best way to make these techniques stick is to use them. Practice mode gives you a fresh small board any time, with no pressure and no streak on the line.
Start practicing →FAQ
Are nonograms hard?
Nonograms range from a few minutes for a small 5×5 picture to a real challenge on a 15×15 or larger grid. The rules never change, though — every puzzle is solved with the same handful of logic techniques, so the more you play, the faster you'll spot them.
What do the numbers mean?
Each number is the length of one unbroken run of filled cells in that row or column, listed in the order the runs appear. A clue of "3 1" means: somewhere in that line there's a run of 3 filled cells, then at least one empty cell, then a run of 1 filled cell — in that order, left to right or top to bottom.
What does a 0 clue mean?
A clue of 0 means the entire row or column is empty — no filled cells anywhere in that line. It's one of the easiest clues to act on: you can safely mark every cell in that line as empty right away.
Should I guess in nonograms?
A well-formed nonogram — including every daily puzzle on Nonogram Hub — always has exactly one solution that can be reached through logic alone, with no guessing required. If you feel like you have to guess, it usually means there's still a deduction available that you haven't spotted yet — re-check the lines with the biggest numbers or the ones closest to being finished.
What is the difference between nonogram and Picross?
They're the same puzzle by different names. "Nonogram" is the general term (also called griddlers or picture cross); "Picross" is short for "picture crossword" and became popular through Nintendo's Picross video game series. The solving logic is identical either way.
How do I get better at nonograms?
Play regularly, start with smaller grids before moving to 15×15 boards, and lean on the overlap method whenever a clue is large relative to the line's length. Marking cells you're certain are empty (not just filling the ones you're sure about) is often what unlocks the rest of a stuck line.