How to play
A nonogram is a picture hidden in a grid, described only by numbers. Each row has a clue to its left and each column a clue above it. The clue lists the lengths of the filled runs in that line, in order. A row clue of 3 1 means: somewhere in the row, three filled cells in a row, then at least one empty cell, then one more filled cell. Any other cells in that row are empty.
Your job is to fill exactly the cells that satisfy every row and every column at once.
Controls
- ■ Fill and ✕ Mark empty choose your tool. Fill paints a solid cell; Mark empty puts a small cross in a cell you’ve proven is blank.
- Tap a cell to apply the tool. Tapping a cell that already has that mark clears it.
- Drag to paint a run. The stroke locks to the row or column you start moving along, so a slightly wobbly swipe won’t spill into the next line. If the first cell you touch already carries the tool’s mark, the drag erases instead.
- Undo steps back through your changes. Hint settles one cell for you, filling or crossing it; if you’ve made a mistake, the hint fixes a wrong cell first. New puzzle starts another grid.
The keyboard works too: move between cells with the arrow keys, and press Enter or Space to apply the current tool.
Feedback while you solve
When a line’s filled cells match its clue exactly, its numbers fade out. If what you’ve filled and crossed in a line can no longer fit its clue, the filled cells in that line are flagged as a conflict and shake, so you can find a mistake early. Crosses are notes only: the puzzle is solved as soon as the filled cells are right, crossed or not.
Sizes and pictures
- Easy is 5 × 5 with a random pattern. Good for learning the logic.
- Medium is 10 × 10 and hides one of twelve drawings, such as a heart, a mushroom, a duck, an umbrella or a cat.
- Hard is 15 × 15 and hides one of five larger drawings: a sailboat, a rocket, a flower, a snowman or an owl.
On Medium and Hard, a solved grid turns into the picture in colour. Your time and the number of hints you used are shown at the end.
Every puzzle in the game is checked by a line-by-line solver before you see it. If that solver can’t finish it using only one row or column at a time, the puzzle isn’t used. So you never need to guess, and each puzzle has exactly one solution.
Strategy
Nonograms reward a handful of reliable techniques. Use them in roughly this order.
1. Overlap in long runs. Slide a run as far left as it can go, then as far right. Cells covered in both positions must be filled. In a 10-cell row with the clue 7, the run starts somewhere from cell 1 to cell 4, so cells 4 to 7 are always filled. The rule of thumb: a run of length n in a line of length L fixes 2n − L cells in the middle, when that number is positive.
2. Full lines. Add the clue numbers plus one gap between each pair. If the total equals the line length, there’s only one arrangement. In a 10-cell line, 4 2 3 needs 4 + 2 + 3 + 2 gaps = 11 cells, which is too many, so that clue can’t appear there; 5 4 needs 10 and is fully decided.
3. Edges anchor runs. A filled cell touching the border must belong to the first (or last) run of that line, which tells you how far that run reaches. Cross the cell just past it.
4. Finish and cross. Once a line’s runs are all placed, cross every other cell in it. Those crosses are what unlock the perpendicular lines.
5. Gaps too small to use. If a stretch of open cells between crosses is shorter than every run that could still go there, it must be empty.
6. Alternate directions. Every cell you settle in a row is new information for its column. Sweep the rows, then the columns, then the rows again. On a 15 × 15 picture, progress usually comes in waves like this.
If a line refuses to budge, look at the lines that cross it. The answer is almost always one step away in the other direction. And when you’re truly stuck, a single Hint is a cheap way to see where the logic goes next.
Like number logic? Try Kakuro for sums or Star Battle for another grid you fill by elimination.
If you enjoy Nonogram, try Number Target or Pair Up next.
