Fill the grid from the row and column clues: 5×5, 10×10 and 15×15 puzzles, each with one solution you can reach by logic alone
A nonogram is a grid puzzle where number clues tell you which squares to fill. The numbers beside each row and above each column give the lengths of the runs of filled squares in that line, in order, with at least one empty square between runs. Work out every square from those clues and the finished grid is solved. Ours come in 5×5, 10×10 and 15×15, a new random grid every time, and each one has exactly one answer that you can reach by reasoning alone: the generator only keeps a puzzle if a line-by-line solver can finish it without a single guess.
Pick a grid size: 5×5 is a quick warm-up, 10×10 takes a few minutes, 15×15 is a proper sit-down puzzle.
Press New puzzle. Clues appear to the left of every row and above every column.
Read a clue such as 3 1: somewhere in that line there is a run of three filled squares, then at least one gap, then a single filled square, and nothing else is filled.
With the Fill tool, tap a square to fill it; tap it again to clear it. Drag across squares to fill several at once.
Switch to Cross out (or right-click) to mark squares you have proved are empty. Crosses do not count toward the answer; they are notes for you.
On a keyboard, move with the arrow keys, press Space to fill and X to cross out.
A clue turns grey when its line matches it. When every row and column matches, the puzzle is solved and your time is recorded.
Deductive reasoning with many constraints at once. Every move is a small proof: this square must be filled because every way of fitting the clue covers it, or it must be empty because no way of fitting the clue reaches it. Along the way you practise holding a few possibilities in mind, checking each against what is already known, and switching attention between rows and columns as each new square opens up the lines that cross it.
Start with the big clues. A run of 8 in a 10-square line always covers the middle six squares, however it is placed, so fill those first.
Add up a clue: runs plus the gaps between them. If 4 2 3 needs 4 + 1 + 2 + 1 + 3 = 11 squares in an 11-wide line, the whole line is fixed.
Lines with a 0 clue are completely empty. Cross them out at once; they often unlock the lines that cross them.
Cross out generously. A square you know is empty narrows every clue that passes through it.
After you fill a square, look at its column or row straight away; the new square often forces more.
When a run is complete, cross out the squares at both ends of it.
If you are stuck, press Check: any filled square that is wrong turns red. Your time keeps running, and the win screen shows how many checks you used.
A nonogram is a logic puzzle on a grid. Each row and column has a list of numbers giving the lengths of the unbroken runs of filled squares in that line, in order. You fill squares until every line matches its clue. The finished grid is usually a picture in printed puzzles; here the grids are random patterns, so every puzzle is new.
A clue of 2 3 means a run of two filled squares, then one or more empty squares, then a run of three, and every other square in the line is empty. A clue of 0 means the whole line is empty. The order matters: 2 3 and 3 2 are different lines.
No. Before a puzzle is shown, our generator solves it with a program that only uses one row or one column at a time and only fills a square when every possible arrangement of that clue agrees on it. If the program cannot finish, the puzzle is thrown away. So every puzzle here can be solved by logic alone, and it has exactly one solution.
Three: 5×5 (easy), 10×10 (medium) and 15×15 (hard). Each size keeps its own best time in your browser.
It turns red any square you filled that is not part of the solution. It does not fill anything for you and it does not reveal empty squares. The number of checks you used is shown when you finish.
Yes. On a keyboard, arrow keys move between squares, Space fills and X crosses out. On a phone, tap or drag to fill, and switch the tool to Cross out to mark empty squares. Large grids scroll sideways inside the board if the screen is narrow.
It is free with no sign-up. Your best time for each size and your total number of solved puzzles are saved in this browser only.