How to Play
Nonograms (also called Picross or Griddlers) are logic puzzles where you fill in cells on a grid based on number clues. Each row and column has a set of numbers that tell you how many consecutive groups of filled cells exist in that line.
For example, a clue of 3 1 means there is a group of 3 filled cells, at least one empty cell, then a group of 1 filled cell. Your goal is to figure out exactly which cells to fill and which to leave empty.
Controls
- Left-click (or tap) to cycle a cell: empty → filled → X-mark → empty
- Right-click (or long-press on mobile) to toggle an X-mark on an empty cell
- Arrow keys to move between cells
- Space / Enter to fill or cycle the selected cell
- X key to toggle an X-mark on the selected cell
- Ctrl+Z to undo the last action
Difficulty Levels
- Easy — 5×5 grid. Great for learning the basics.
- Medium — 10×10 grid. A solid challenge for most players.
- Hard — 15×15 grid. Requires careful logic and patience.
- Expert — 20×20 grid. The ultimate test of nonogram skill.
Features
- Auto-cross clues — completed row and column clues are automatically struck through
- Row/column highlighting — hover or select a cell to highlight its row and column
- Error checking — use the Check button to highlight incorrectly filled cells
- Undo — take back your last move at any time
- Timer & stats — track your solve times, win rate, and streaks per difficulty
Tips
- Start with the biggest clues — rows or columns with large numbers have fewer possible positions, making them easier to solve.
- Use X-marks — marking cells you know are empty helps narrow down the remaining possibilities.
- Look for overlaps — if a clue number is more than half the row/column length, some cells in the middle must be filled regardless of position.
- Check completed lines — when a clue is struck through, fill the remaining empty cells with X-marks to avoid confusion.
- Work both directions — alternate between solving rows and columns. Progress in one direction often reveals information for the other.
Frequently Asked Questions
What are Nonograms?
Nonograms (also called Picross or Griddlers) are logic puzzles where you fill in cells on a grid based on number clues for each row and column. Solving the puzzle reveals a hidden pixel picture.
What do the number clues mean?
Each number represents a consecutive group of filled cells in that row or column. Multiple numbers mean multiple groups separated by at least one empty cell, in the order listed.
What difficulty levels are available?
There are four levels: Easy (5x5 grid), Medium (10x10), Hard (15x15), and Expert (20x20). Larger grids require more advanced logic and patience.
What does an X-mark mean?
An X-mark indicates a cell you have determined must be empty. Placing X-marks helps you track which cells cannot contain a filled group, making it easier to solve the remaining unknowns.
Is there an undo button?
Yes. Press Ctrl+Z or use the Undo button to reverse your last action at any time during solving.
About Nonograms
Nonograms were invented independently in 1987 by Non Ishida in Japan and by Tetsuya Nishio. The puzzles became popular in Japan and spread worldwide under many names including Picross, Griddlers, Paint by Numbers, and Hanjie. They combine logical deduction with the satisfaction of revealing a hidden picture, making them one of the most beloved puzzle formats alongside Sudoku and crosswords.
From the build: the cell-cycle order — empty to filled to X to empty — was the third version we tried. Filled-then-X-then-empty felt more natural in our heads, but in playtesting people kept accidentally erasing progress by tapping a filled cell twice. The current order lets you mis-tap once without losing work. On the 20x20 Expert boards, auto-crossing completed clues turned out to matter more than we expected; without it your eyes burn out scanning a 40-clue side panel for which numbers are still in play.