How to play
A nonogram is a grid with number clues beside each row and above each column. Each clue lists the lengths of the filled blocks in that line, in order. A row marked 3 1 has a block of three filled squares, then at least one empty square, then a single filled square. Fill the right squares and a picture or pattern appears.
- Fill mode paints squares. Cross mode marks squares you know are empty. On a computer, right-click always places a cross.
- Drag to paint a run of squares in one go. Press a filled square again to clear it.
- A clue fades when its line matches it, so you can see what is left.
- Show mistakes marks squares that disagree with the solution. Hint fixes a wrong square or fills one correct square.
- Keyboard: arrow keys move, Space fills, X crosses, Backspace clears, Ctrl+Z undoes.
Sizes
5×5 puzzles take a minute and teach the basic moves. 10×10 is the classic size, and 15×15 puzzles need more overlap counting and more patience. Turn on Picture puzzles for hand-drawn pictures at 10×10 and 15×15. All other puzzles are random patterns smoothed into shapes, each one checked so it can be solved by logic alone.
Solving techniques
Overlap counting
In a 10-square row with a clue of 7, slide the block as far left as it goes, then as far right. The two positions overlap on squares 4 to 7, so those four squares must be filled whatever happens. The rule of thumb: a block of length L in a line of length N always fills at least 2L minus N squares in the middle when it is the only block.
Add up the clue
Add the blocks plus one gap between each pair. If a 10-square row says 4 5, that is 4 + 1 + 5 = 10, so the whole row is decided. Clues that add up close to the line length are the best place to start.
Use the edges
A filled square next to the edge of the grid must belong to the first block in that line. If the first clue is 3 and the first square is filled, squares one to three are filled and the fourth is empty.
Cross what cannot be filled
When a line's clue is complete, cross the rest of it. Crosses become information for the crossing lines, and that is how a solve keeps moving.
Background
Nonograms were created in Japan in the late 1980s, and the name joins the name of one of their inventors, Non Ishida, with the word diagram. They are also known as griddlers, paint by numbers and hanjie. For another logic grid, try Sudoku or the number clues of Minesweeper.
Questions
Do I ever need to guess?
No. Every puzzle here was checked with a line-by-line solver, so you can always find the next square by looking at a single row or column and its clue.
What do the crosses do?
Crosses are your own reminders for squares that must stay empty. They are not required to finish, and the puzzle counts as solved as soon as the filled squares match every clue.
What happens after I have seen all the pictures?
With Picture puzzles on, you get the hand-drawn pictures for that size first. Once you have played them all, new puzzles are random patterns that are still guaranteed solvable by logic.
Can I paint several squares at once?
Yes. Press on a square and drag along the row or column. The stroke stays on the line you started, so a shaky hand will not spill into the next row.