How to play nonograms
Nonograms — also called picross, griddlers, hanjie or paint-by-numbers — are grid puzzles where numeric clues describe a hidden pixel picture. Solve the logic, and the picture appears.
The rules
- The numbers beside each row and above each column list the lengths of the runs of filled cells in that line, in order.
- Between two runs there is at least one empty cell.
- A clue of
0means the line is completely empty.
That’s the whole ruleset. A clue like 2 3 means: somewhere in this line
there are 2 filled cells together, then a gap of one or more cells, then 3
filled cells together.
A worked 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 ×.Compare the two boards against the rules: every row with clue 1 1 has
exactly two single filled cells with a gap between them, the 5 row and
5 columns are filled end to end, and each 1 column has its lone filled
cell where the crossbar sits. Notice that the solver marked the empty cells
with × — that isn’t decoration, it’s how you record what you’ve deduced.
Core techniques
Full lines
If the clue accounts for the entire line, fill it all in. In a 5-wide line,
5 fills everything; 2 2 also fills everything (2 + 1 gap + 2 = 5).
Overlap
The most important technique. Imagine pushing a run as far left as it can go,
then as far right. Any cells covered in both extremes must be filled. In
a 5-wide line with clue 4, the run occupies cells 1–4 or 2–5 — so cells
2–4 are certainly filled.
Edges
Once a filled cell touches a wall (or a known empty cell), the nearest clue run is anchored: you can often complete the run and mark the cell after it empty.
Mark the empties
Marking cells you know are empty (usually with an ×) is as valuable as filling. Completed lines can be closed off entirely, which anchors runs in the crossing lines.
Iterate
Every cell you determine adds information to its row and its column. Sweep the grid repeatedly — lines that were stuck often open up after a crossing line places one cell.
No guessing — guaranteed
Some nonograms published elsewhere have multiple solutions or force you into trial and error. Every puzzle on this site is machine-verified to have exactly one solution reachable with the techniques above — if you’re stuck, there is always a logical next step somewhere on the board.
Ready? Start with the bronze nonogram — its sixteen puzzles are the easiest on the site — then work your way up through silver to gold, revealing each medal’s picture cell by cell. When the grids get bigger, the solving techniques page is the next thing to read.