How to enter the clues
One line per row in the left box, one line per column in the right box, top to bottom and left to right. Separate the numbers of a single line with spaces or commas. A line with no filled squares at all is written 0, or simply left blank.
The grid size is read from what you type: five lines on the left and five on the right means a 5×5. Nothing to set, and no way to set it wrong. Up to 30×30.
What the verdict means
There are four possible answers, and the difference between them is the whole point.
Solved by pure logic
Every square was proved, one line at a time, without ever assuming anything. This is what a well-built puzzle looks like — and the only kind we ship in Nono. If you were stuck on a grid that comes back with this verdict, you missed a deduction rather than needing luck.
One picture, but a guess was needed
The clues do describe exactly one image, so the puzzle is not broken — but line-by-line reasoning stalls part-way, and getting to the end requires assuming a square and following the consequences until something contradicts. Plenty of published puzzles are like this. It is a legitimate style; it is just not one you can solve by pure reading, and it deserves to be labelled rather than left as a mystery.
Several pictures fit
The clues are satisfied by more than one image. The puzzle is faulty: whichever you choose, you cannot know you were right. The solver shows one of the valid pictures and says how the others differ.
The clues contradict each other
No image satisfies them. Usually a typo — a number too large for its line, or a row and column disagreeing on how many squares are filled in total. That last check is worth doing by hand: the sum of all row numbers must equal the sum of all column numbers, because both count the same filled squares. If they differ, the mistake is found before any solving starts.
Why “no guessing” is the thing worth measuring
A nonogram is a proof, not a maze. Every square you fill should follow from something you already know, and the pleasure of the puzzle comes precisely from that chain never breaking. The moment a grid can only be advanced by trying a square to see what happens, it stops rewarding attention and starts rewarding patience.
This matters more than it sounds, because the two cases are indistinguishable from the player's chair. Someone stuck on a grid cannot tell whether they have missed a deduction or whether the puzzle has run out of them. They blame themselves for a fault in the puzzle, or they gamble on a grid that did not require it. The verdict above exists to settle that.
The engine running on this page is the same one that validates every level in Nono before it ships: any grid that does not come back “solved by pure logic” is thrown away and regenerated. If you want the reasoning behind the techniques it uses, the overlap rule is where to start — it is explained in how to solve a nonogram.
Common questions
Is this a picross solver too?
Yes. Picross, griddler, hanjie, japanese crossword, paint by numbers — different names, identical rules. Anything you can write as row and column run-lengths goes in this box.
How big a grid can it take?
Up to 30 squares on a side. The line solver packs each line into a bitmask, and 30 is where that stops being exact. In practice a 25×25 comes back instantly; the rare puzzle that needs deep searching is given a fixed work budget and will say so rather than hang.
Does anything I type get sent anywhere?
No. The solving happens in your browser — the page makes no network request once it has loaded, and there is nothing on the other end to receive a puzzle.
Can it generate puzzles, not just solve them?
Not on this page. Generating is the harder half: it is easy to draw a picture and read off its numbers, and hard to guarantee the result has exactly one solution reachable without guessing. That is done offline, which is why Nono ships 240 levels rather than making them up as it goes.