Nonograms

How to play nonograms online

A nonogram is a grid of empty squares with a row of numbers at the left of each row and above each column. Those numbers are the clues. Each number is the length of one run of filled squares in that line, and the runs appear in the same order as the numbers, with at least one empty square between two runs. Your job is to fill the right squares so that every row and every column matches its clues. When the last square is right, the picture is complete and the game plays a short reveal.

You do not need to know how nonograms work to start. Pick a small 5x5 puzzle and tap a square: it fills. Tap a filled square and it empties again. Use the Cross tool (or right click on a computer) to put an X on squares you are sure are empty. The crosses do nothing to your score; they are your own notes, and they make the picture easier to see.

• Choose a puzzle from the size tabs: 5x5, 10x10, 15x15, 20x20 or a wide or tall rectangle.
• Read the clue for a line. A clue of 3 1 means a run of three filled squares, then at least one gap, then one filled square.
• Fill what you are sure about and cross out what you know is empty.
• Keep going line by line. Every new square gives new information to the lines that cross it.
• Finish the grid to reveal the picture. There is no move limit and no lives, only the clock.

How to read nonogram clues

The clue for a row sits at its left end and the clue for a column sits above it. A single number, such as 5, means one block of five filled squares somewhere in that line. Several numbers, such as 2 1 3, mean three separate blocks of two, one and three squares in that order from left to right (or top to bottom), each pair separated by at least one empty square. A line with the clue 0 (shown as an empty line) has no filled squares at all.

A useful habit is to add up the clue numbers and the minimum gaps. The line 2 1 3 needs 2 + 1 + 3 = 6 filled squares plus 2 gaps, so at least 8 squares. In a 10-square line that leaves only 2 squares of slack, and that slack is exactly what makes the first deductions possible.

• When a clue is complete, the numbers fade to grey and the leftover empty squares in that line get crossed out for you (you can switch this off in Settings).

How to solve nonograms: the core techniques

Almost every nonogram can be solved with a handful of ideas. They work on one line at a time, then the result feeds the crossing lines. This is the whole method, and it is why our puzzles never need a guess.

• Full lines. If the clue plus its gaps exactly equals the length of the line (for example 3 2 in a 6-square line), the line is fully decided: fill, gap, fill. Start every puzzle by looking for these.
• Overlap (the simple boxes technique). Slide the biggest block as far left as it goes, then as far right. The squares covered both times must be filled. A clue of 8 in a 10-square line fills squares 3 to 8 for certain, because the block can only shift by two.
• Edges. If a square at the very end of a line is filled, the first block must start there, so you can fill the whole first block and cross the square after it. The same works from the other end.
• Simple spaces. If a gap between crosses is smaller than the smallest block that is still unplaced, nothing can go there, so cross it out.
• Glue and joining. If two filled squares are in the same block, everything between them is filled too. If a filled square must belong to a given block, you can often extend it to the block's full length from one side.
• Splitting. A cross in the middle of a long space divides the line into two parts, and each block must fit entirely inside one part. Count which blocks can still fit where.
• Counting remaining blocks. Once the long blocks are placed, the small ones are forced into the leftover spaces. Cross the squares that no remaining block can reach.

Nonogram tips for faster, cleaner solving

Work on the line that has the least slack, not the line you happened to look at last. Slack is the line length minus the clue total and gaps. Rows and columns with a slack of zero are free squares, slack of one or two gives a few overlaps, and anything with a large slack should wait until its crossing lines have been filled.

Cross out as you go. An empty square that stays blank is ambiguous: do you know it is empty, or have you not looked at it yet? Marking it with a cross turns your knowledge into something you can see, and it unlocks edge and splitting deductions. When you pause a puzzle and come back later, the crosses tell you exactly where you were.

Do not guess. Every puzzle here can be solved by looking at rows and columns separately, one after the other. If you feel stuck, loop through the lines again: a new square somewhere almost always gives a line one more deduction. If you really are stuck, the Hint button finds the next certain square and shows you which row or column it comes from, so you can learn the reasoning instead of just copying it.

Nonograms 5x5 to 20x20, plus wide and tall grids

The puzzle shelf has five tabs. The 5x5 puzzles are quick warm-ups of one to three minutes, good for learning. The 10x10 puzzles are the classic size: ten to twenty minutes, with enough clues to need every technique above. The 15x15 puzzles take a good half hour and have long clues. The 20x20 puzzles are large pictures for an evening with a cup of tea. The Wide tab collects rectangles, such as 12 columns by 6 rows, because a nonogram does not have to be square.

In total there are more than 120 shipped puzzles. Some are hand-drawn pixel pictures (a cat, a rocket, a butterfly, a lighthouse, a sailing boat) and the rest are generated ink-blot pictures. The Random puzzle button makes a new picture of the size you have selected, every time, so you can practise as long as you like. Solved puzzles show their finished picture on the puzzle card with your best time.

The daily nonogram puzzle

The Daily puzzle is chosen from the date, so everyone who plays today gets the same picture. It is a 10x10 or 15x15 puzzle, which makes it a good once-a-day habit. Your time for the day is saved, and finishing it marks the day as done on your daily challenge list.

Controls: phone and computer

On a phone, the toolbar at the bottom has a big switch between Fill and Cross, so your thumb never has to hunt for a tiny button. Tap a square to apply the current tool. Drag across several squares to fill or cross a whole line in one stroke: the drag locks to a single row or column once it starts, so a wobbly finger does not paint the wrong squares. Starting a drag on a filled square erases instead of filling, so the same gesture removes mistakes.

On a computer, left click fills, right click crosses, and you can drag the same way. The keyboard works too: the arrow keys move a cursor, Space or Enter fills, X crosses, Z undoes, Y redoes, H gives a hint and P pauses. Press Escape to open or close the pause screen.

• Undo and redo step back through every stroke, including the squares that were crossed out for you automatically.
• Zoom in with the plus button, pinch with two fingers, or hold Ctrl and use the mouse wheel. When you are zoomed in, a third tool called Move appears so you can pan the board with one finger without painting by accident.
• Clear wipes the board after asking for confirmation. Pause hides the board and stops the clock.

Error check, hints and auto cross-out

Three helpers can be used or ignored. The Check button (a shield icon) switches mistake display on: any filled square that should be empty, and any crossed square that should be filled, gets a red outline, or a hatched pattern in colour-blind mode. A small counter shows how many mistakes are on the board. Leave it off if you want the full challenge and a cleaner time.

The Hint button finds a square you can deduce from the squares you already have right. It fills or crosses that square and flashes the row or column the deduction came from. Hints are counted and shown in your result, so you can try to finish a puzzle with none.

Auto cross-out, on by default, crosses the empty squares of a row or column the moment its clue is satisfied. It saves a lot of tapping on big grids and doubles as a quiet confirmation that a line is correct.

Colour themes and colour-blind friendly mode

Choose the ink your filled squares use: classic black ink, tomato, cobalt, teal or pink. When you finish a puzzle the picture is revealed in a small palette of print colours, from top to bottom of the grid. The Colour-blind friendly switch in Settings changes the palette to blue and orange tones that stay distinct for the common kinds of colour blindness, draws crosses thicker, and marks mistakes with diagonal stripes instead of relying on red alone.

Nonogram, Picross, Griddlers and Hanjie: what is the difference?

They are the same puzzle with different names. Non Ishida and Tetsuya Nishio, two Japanese puzzle designers, invented it independently in 1987. Nintendo made it famous as Picross (picture crossword) from the 1990s, newspapers in Britain called it Griddlers, Eastern Europe knows it as Hanjie, and the generic English word nonogram comes from Ishida's first name. In French you will see nonogramme or picross, in German Nonogramm or Bilderrätsel, in Dutch a Japanse puzzel, and in Spanish nonograma or crucigrama japonés. Some apps add colour clues to the rules; this game uses the classic black-and-white kind, where the picture is revealed in colour at the end.

How we guarantee a single solution

A badly made nonogram can have several valid answers, and then the only way through is a guess. That is not how a logic puzzle should feel. Every puzzle here is run through a line solver before it ships: a program that applies the line techniques above, over and over, to see whether the clues alone fill the whole grid. If it does, the solution is unique and the puzzle is solvable by logic. Generated puzzles are kept only when they pass that same test, and the test runs again whenever the code changes. Your progress is saved in your browser, so you can leave a puzzle half done and continue it later.