Nonogram
Fill the grid by the numbers and reveal the hidden picture.
Tap to fill a cell; switch to the × tool (or right-click) to mark cells you know are empty. The numbers give the lengths of the filled blocks in each row and column, in order — every puzzle is solvable by pure logic, no guessing needed.
About Nonograms
Nonograms — also known as Picross, Griddlers or Hanjie — are Japanese picture-logic puzzles from the late 1980s. The numbers beside each row and above each column tell you the lengths of the consecutive filled blocks in that line, in order, with at least one empty cell between blocks. Deduce which cells are filled and a hidden pixel picture emerges.
Ludingo has three sizes — easy 5×5, medium 10×10, hard 15×15 — with 1000 numbered puzzles per difficulty. Every puzzle is generated so it can be solved by pure line-by-line logic: no guessing, ever, and exactly one solution. Puzzles are fixed and shared, so puzzle #217 is the same picture for everyone — race friends on the identical grid via a share link. Free, unlimited, no account needed.
How to play
- The numbers next to a row (or above a column) are the lengths of its filled blocks, in order. "3 1" means a block of 3, then at least one empty cell, then a single cell.
- Tap a cell to fill it. Use the × tool (or right-click) to mark cells that must stay empty — marks are notes and don't affect winning.
- Blocks in the same line are separated by at least one empty cell.
- Fill every correct cell to complete the picture. Cleared rows and columns dim their numbers so you can track progress.
How to solve Nonograms — strategy and techniques
Start with the big numbers. A block longer than half the line pins down its middle cells no matter where it slides: in a 10-wide line an 8-block always covers the central six cells. Fill that guaranteed overlap first — it is the single most productive opening move.
Work the edges. Once a filled cell touches the border, its whole block is anchored: count it out, close it with an × on each side, and the line often collapses. Full-line clues (a 15 in a 15-wide row, or numbers plus gaps that add up exactly) can be completed immediately.
Mark empties as aggressively as you fill. When a line's blocks are all placed, × out everything else; when a block is complete, cap both ends. Those × marks are what turn the crossing lines into new deductions — most stalls come from unmarked empties, not missing fills.
Alternate rows and columns. Every cell you decide in a row is new information for its column and vice versa — sweep row-by-row, then column-by-column, and revisit lines whose numbers dimmed. On Ludingo no puzzle ever needs a guess, so a stall always means a line still has something to give.
Tips for faster solves
- Open with the overlap trick on every line where the biggest block is longer than half the width.
- An empty clue (0) or a full-width number finishes its whole line instantly — clear those first.
- Cap completed blocks with × on both sides right away; those marks unlock the crossing lines.
- Drag to paint long runs in one stroke; right-click (or the × tool) to mark empties without switching pace.
Questions about Nonograms
What are the rules of a nonogram?
Each number sequence describes its row or column: the numbers are the lengths of the consecutive filled blocks, in order, with at least one empty cell between them. Fill the cells so every row and every column matches its numbers — the filled cells form a hidden picture.
Can nonograms be solved without guessing?
On Ludingo, always. Every puzzle in the pool is verified to be solvable step by step with line logic alone, which also guarantees exactly one solution. If you feel forced to guess, there is always a logical deduction you haven't spotted yet.
What do the × marks do?
The × marks cells you have deduced must stay empty. They are pure notes — only the filled cells decide the win — but marking empties is the key technique: a completed count of empties often forces the remaining fills.
Are the puzzles random or shared?
Shared. Each difficulty has 1000 fixed, numbered puzzles — #217 is the same picture for everyone. Share the URL and your friends race you on the identical grid.
What is the difference between nonogram, Picross, Griddlers and Hanjie?
They are the same puzzle under different trade names: Nintendo popularised it as Picross, magazines print it as Griddlers or Hanjie, and "nonogram" honours its co-creator Non Ishida. The rules are identical everywhere.
Can I play nonograms on my phone?
Yes — the board works in any mobile browser. Tap to fill, switch to the × tool for marking, and drag across cells to paint a whole run in one stroke. On desktop you can also right-click to mark.