Picross (Nonogram)

Picross (also called Nonograms, Hanjie, Griddlers, or Picture Cross) is the logic puzzle where numerical clues describe the row and column patterns of a hidden picture; you mark cells “filled” or “empty” based on pure deduction. Solve correctly and the filled cells reveal a pixel-art image. Picross was popularized by Nintendo’s “Mario’s Picross” (Game Boy, 1995) and has since become a beloved staple of puzzle game collections worldwide.

How to play

• A grid (e.g. 10×10 or 15×15) starts empty.
• Numbers along each row tell you the run-lengths of filled cells in that row. “3 2” means a run of 3, then at least 1 empty cell, then a run of 2 — in that order.
• Same for columns.
• Click to fill a cell (it’s filled). Right-click or shift-click to mark “empty” (it’s definitely not filled).
• Use the row and column clues together to deduce every cell’s state.
• Solve all cells correctly = revealed image. Each mistake may or may not be flagged (depending on game variant).

Beginner strategy

• Start with large clues. A clue of “8” on a 10-column grid means at least 8 cells are filled with some flexibility at start/end. The middle 6 are definitely filled.
• Use the “overlap” technique. For a clue of N on a row of length L: the LEFT-most position has the first cell at col 0; the RIGHT-most has the last cell at col L-1. Any cell that’s filled in both extreme positions is definitely filled.
• Cross-reference rows and columns. A cell is at the intersection of a row clue and column clue. If either constrains it to filled or empty, you have the answer.
• Mark empty cells too. Knowing what ISN’T filled is just as valuable as knowing what is.
• Start with edges. Corner rows/columns often have unique-deduction starting points.

Intermediate strategy

• Edge logic. A clue of “5” with a cell already marked filled at column 0: the 5-cell run must start at column 0 or earlier. Since column 0 is the boundary, the run starts AT column 0 and ends at column 4.
• Gap logic. Between consecutive clue runs there’s at least 1 empty cell. So a row with clues “3 4” needs at least 8 cells (3+1+4=8). On a 10-column row, this leaves 2 cells of slack.
• Slack distribution. The total slack is L – (sum of clues + number of gaps). Slack tells you the “wiggle room” in positioning.
• Symmetric clues. A row reading “2 2” on a 6-column grid has only one valid configuration: filled-filled-empty-empty-filled-filled.
• Chain deduction. Solving one row often reveals new constraints on intersecting columns, which then reveals other rows. Work in chains.

Advanced strategy

• Probability-based marking. When no logical deduction works, calculate which cells have the highest probability of being filled. Most variants don’t penalize errors, so probabilistic guesses are sometimes valid.
• Mark with confidence. Don’t pencil-fill cells. Only fill cells when you’re certain. Uncertainty leads to cascading errors.
• Use both row and column simultaneously. Top solvers process rows and columns in parallel, holding two perspectives.
• Reading the picture. If the partial picture starts to look like something (a face, an object), use the recognition to inform deductions.
• The “double-fill” rule. Two consecutive filled cells force the cells two positions earlier and later to be either empty or part of a long run.

Picross history

• 1987 — Tetsuya Nishio: creates Nonograms in Japan as “Window Art Puzzles” for puzzle magazines.
• 1990 — Japan rights to Non Ishida: Ishida’s name becomes synonymous with the puzzle in Japan.
• 1995 — Mario’s Picross: Nintendo licenses the format for Game Boy. Mario’s Picross becomes a worldwide hit, popularizing the puzzle outside Japan.
• 1996-2000 — Picross sequels: Mario’s Super Picross, Picross 2, several Nintendo-published sequels.
• 2014 — Picross e series: Jupiter Corporation releases dozens of Picross e games for Nintendo 3DS / Switch — driving a Picross resurgence.
• 2020s — mobile Picross: “Pixel Combats”, “Nonogram King”, “Picross Touch” — Picross is firmly established on mobile.

Why Picross is loved

• No guessing. Well-constructed Picross has a unique solution reachable by pure logic.
• Visual reward. Solving reveals a picture — a satisfying payoff beyond just “checkmark complete”.
• Scaling difficulty. 5×5 puzzles are trivial; 20×20 puzzles are demanding; 50×50 puzzles are full-day puzzles.
• Meditative. The deduction process is calming, similar to Sudoku.
• Theme-able. Picross variants exist for every interest — Disney characters, anime, animals, food.

Common mistakes

• Filling cells you’re not certain about. One wrong fill ripples into multiple wrong deductions.
• Ignoring “empty” markings. Marking definite-empty cells constrains intersecting clues.
• Solving rows in isolation. Use column information continuously.
• Trying to “see the picture”. Bias yourself by what you expect — sometimes the picture doesn’t help, sometimes it does. Don’t depend on it.
• Restarting after one mistake. Most Picross apps let you continue. Just correct the error.

Variants

• Color Picross. Cells can be filled with different colors. Clues specify color sequences.
• Hexagonal Picross. Hex grid instead of square.
• 3D Picross / Picross 3D. 3D voxel puzzles — Nintendo’s Picross 3D series.
• Picross S (Switch). Modern Picross series for Nintendo Switch.
• Pic-A-Pix. Color-cell variant.
• Mario’s Picross (Game Boy). The classic.

FAQ

• Q: Do I need to guess? A: Properly-constructed Picross is fully solvable by logic alone. Random or amateur puzzles sometimes need guesses.
• Q: What does “3 2” in a clue mean? A: A run of 3 filled cells, at least 1 empty, then a run of 2 filled cells — in that order.
• Q: How big is a typical Picross? A: Mobile and console games range from 5×5 (intro) to 25×25 (challenging). 15×15 is a typical mid-difficulty.
• Q: Are mistakes penalized? A: In Mario’s Picross style, mistakes cost time. In freestyle Picross, mistakes are just corrected. Modes vary.

For other logic puzzles, try Sudoku, Minesweeper, Lights Out, or Crossword.