How to play nonograms
Nonograms — also called picross, griddlers, hanjie, or paint-by-numbers — are logic puzzles that reveal a pixel picture. The clues tell you which cells to fill; your job is to work out exactly where every filled run belongs.
Reading the clues
The numbers beside a row describe that row from left to right. The numbers above a column describe that column from top to bottom.
- A clue of
3means one unbroken run of exactly three filled cells. - A clue of
1 2means a run of one, then later a run of two. - Separate runs always have at least one empty cell between them.
- A clue of
0means the entire line is empty.
The clues give the lengths and order of the runs, but not their positions. For
example, 1 2 does not say how large the gap is or whether empty cells appear
before the first run or after the last one.
A complete example
The puzzle as you receive it…
…and solved: the letter H
5 fills the whole row; the 1 1 rows have one filled cell at each end; columns one and five read 5, so they are filled top to bottom. Empty cells are marked ×.The 5 clues force a full row or column immediately. Each 1 1 row then has
one filled cell at either end, with empty cells between them. The × marks are
known empty cells; recording them is just as important as recording filled
cells.
Your first deductions
Fill lines with no spare space
If the runs and their required gaps use the whole line, every cell is known.
A five-cell line with clue 5 is completely filled. A five-cell line with
clue 2 2 is also complete: two filled cells, one required gap, then two more.
Use overlap
Imagine placing a run as far toward each end of the line as the clue allows. Cells covered in both extreme placements must be filled, even though the exact position of the complete run is not known yet.
A full line: clue 2 2
Two runs of 2 plus their required gap use all 5 cells.
Overlap: clue 4 in 5 cells
The middle 3 cells are covered in every possible position.
Close finished runs
When a run has reached its clue length, the cell immediately before and after it must be empty. If the run touches an edge, only the other end needs an ×.
Cross-check rows and columns
Every deduction belongs to two lines. A cell found from a row may create an overlap, complete a run, or eliminate a gap in its column. Keep alternating between rows and columns; a stuck line often becomes useful after one crossing cell changes.
A reliable solving routine
- Start with
0clues, full lines, and the largest clues. - Fill only cells that must belong to a run.
- Mark cells that must be empty with ×.
- Close completed runs and completed lines.
- Recheck every crossing row and column, then repeat.
You never need to identify the picture in advance. Treating it as a picture can tempt you to fill a cell because it “looks right,” which is guessing rather than deduction.
Controls on this site
Click or drag to fill cells. Clicking a filled cell changes it to ×; clicking again clears it. Right-clicking marks an empty cell directly. Your unfinished board is saved automatically in this browser.
Common mistakes
- Letting runs touch: clues
2 1require at least one empty cell between the run of two and the run of one. - Changing the order: the runs must appear in the same order as the clues.
- Stopping after filling: known empty cells often provide the boundary that makes the next deduction possible.
- Guessing from the emerging picture: use only the row and column clues.
No guessing required
Every nonogram on this site is machine-verified to have exactly one solution that can be reached with row-and-column logic. If you are stuck, another line still contains a deduction; you do not need trial and error.
Ready to play? Start with the bronze medal puzzles. When those techniques feel natural, the advanced solving techniques guide covers slack, glue, gap elimination, and more.