A Nonogram, also called Picross, Hanjie or griddlers, is a picture logic puzzle. The numbers beside each row and above each column give the lengths of the consecutive filled runs in that line, in order, with at least one empty cell between runs. You fill the cells the clues demand and leave the rest empty, revealing a piece of pixel art.

What is the overlap trick in Nonograms?

Overlap is the core opening technique. When a clue is large compared with its line, the run cannot move far enough to clear the centre, so some cells are filled wherever it sits. Slide the run as far one way as it goes, then as far the other, and fill every cell covered both times. In a 9-wide line, a clue of 7 always fills the middle five cells.

How do you start a Nonogram puzzle?

Begin with the lines that have the largest clues relative to their length and fill the overlapping cells those clues force. Mark cells you know are empty with an X, since ruled-out cells are as useful as filled ones. Then cross-reference: each filled or empty cell constrains the line that crosses it, opening up the next deduction.

Why should you mark empty cells in a Nonogram?

Empty marks carry as much information as filled cells. They cap completed runs, block runs in crossing lines and stop you from refilling cells you have already ruled out. On Puzzle Lair only the filled cells are required to win, but marking the empties is how the puzzle is meant to be solved, and it keeps your deductions sound so the board is right when you press Check.

Does solving a Nonogram ever require guessing?

No. Every Puzzle Lair Nonogram is a hand-designed picture with exactly one solution reachable by pure logic. Being stuck means there is a deduction you have not spotted yet, often an overlap you have not measured or a crossing line whose empty marks force a run. When you think the picture is complete, press Check to test the board. There is no mistake limit.

Solving guides

From the rulebook

How to Solve Nonograms

Nonograms, also known as Picross, Hanjie or griddlers, are picture logic puzzles. The numbers beside each row and above each column give the lengths of the consecutive filled blocks in that line, and solving every line reveals a piece of pixel art. The clues feel sparse at first, but each cell you fill or rule out tightens the lines that cross it. This guide takes you from the rules to the techniques that crack hard grids without guessing.

Play Nonogram

The rules of Nonograms

A Nonogram is a grid with a list of numbers beside each row and above each column. Those numbers give the lengths of the consecutive runs of filled cells in that line, in the order they appear, with at least one empty cell between runs. A row clue of 4 2 means a run of four filled cells, then a gap of one or more empty cells, then a run of two, reading left to right.

Your job is to fill every cell that belongs to a run and leave the rest empty until the hidden picture appears. Mark the cells you know are empty so you do not lose track of them, and erasing is always free. Entries give no live feedback as you play, so when you think the picture is complete, press Check to test the board. There is no mistake limit, so you can keep editing or clear the board and start over.

Start with the overlap trick

The single most important technique is overlap. When a clue is large compared with the length of its line, the run cannot move far enough to clear the middle, so some cells are filled no matter where it sits. In a 9-wide row, a clue of 9 fills the whole line, and a clue of 7 guarantees the middle five cells whether the run hugs the left edge or the right.

To find the overlap, imagine sliding the run as far left as it goes, then as far right, and fill every cell that is covered both times. The bigger the clue relative to the space, the wider the guaranteed band. These forced cells are your first confident fills, and they seed deductions in every column they touch.

Mark empty cells as you go

Ruled-out cells are as informative as filled ones, so mark every cell you know is empty. When a line is fully solved, mark all its remaining cells empty at once. When a run is complete, cap both of its ends with an empty mark, since the clue forbids the run from growing any longer.

A clue of 0, or a line whose runs are all placed, means every other cell in that line is empty. Those empty marks then block runs in the crossing lines, often forcing a run hard against them. Keeping the empties up to date is what turns a tangle of half-solved lines into a chain of forced moves.

Anchor runs against edges and empties

A run pinned against a wall is easy to place. If the first clue in a row is 3 and the cell at the left edge is already filled, that run must start at the edge, so fill the first three cells and mark the fourth empty. The same works against any empty mark: a run that cannot fit before a known empty cell is pushed past it.

Edge logic compounds with the clue order. Because the clues are listed in sequence, the first run must come before the second, the second before the third, and so on. Work out the leftmost each run could start and the rightmost it could end, and any cell covered in every valid arrangement is forced. Filled cells near an edge often fix a whole run at once.

Cross-reference rows and columns

Nonograms are solved by playing rows against columns. Every cell answers to both its row clue and its column clue, so a cell forced filled by a row deduction immediately constrains its column, and an empty mark from a column can block a run in its row. After working a line, scan the lines that cross your new marks for fresh forced cells.

Apply the techniques in order: fill the overlaps first, mark the empties, anchor the runs against edges and known empties, then loop the row-and-column cross-referencing as the picture fills. On Puzzle Lair every Nonogram is a hand-designed picture with a unique, guess-free solution, so if you are stuck there is always a deduction waiting, never a guess. The 17 by 17 grids are what make the hard set a genuine workout.

Frequently asked questions

What is a Nonogram?: A Nonogram, also called Picross, Hanjie or griddlers, is a picture logic puzzle. The numbers beside each row and above each column give the lengths of the consecutive filled runs in that line, in order, with at least one empty cell between runs. You fill the cells the clues demand and leave the rest empty, revealing a piece of pixel art.
What is the overlap trick in Nonograms?: Overlap is the core opening technique. When a clue is large compared with its line, the run cannot move far enough to clear the centre, so some cells are filled wherever it sits. Slide the run as far one way as it goes, then as far the other, and fill every cell covered both times. In a 9-wide line, a clue of 7 always fills the middle five cells.
How do you start a Nonogram puzzle?: Begin with the lines that have the largest clues relative to their length and fill the overlapping cells those clues force. Mark cells you know are empty with an X, since ruled-out cells are as useful as filled ones. Then cross-reference: each filled or empty cell constrains the line that crosses it, opening up the next deduction.
Why should you mark empty cells in a Nonogram?: Empty marks carry as much information as filled cells. They cap completed runs, block runs in crossing lines and stop you from refilling cells you have already ruled out. On Puzzle Lair only the filled cells are required to win, but marking the empties is how the puzzle is meant to be solved, and it keeps your deductions sound so the board is right when you press Check.
Does solving a Nonogram ever require guessing?: No. Every Puzzle Lair Nonogram is a hand-designed picture with exactly one solution reachable by pure logic. Being stuck means there is a deduction you have not spotted yet, often an overlap you have not measured or a crossing line whose empty marks force a run. When you think the picture is complete, press Check to test the board. There is no mistake limit.

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