Picross (Nonogram)
Officially Picross / Nonogram / Griddler
Logic puzzle where clues at row + column edges tell player how many consecutive cells to fill — solving reveals hidden pixel-art image. Invented by Non Ishida (JP) 1987; popularised by Nintendo Picross (Game Boy 1995) + newspaper 'Hanjie' puzzles.
What is Picross (Nonogram)?
Picross (also known as Nonogram, Griddler, Hanjie, Paint by Numbers, or Logic Art) is a logic puzzle where players fill cells in a grid based on numeric clues at the edges of each row + column. Clues describe how many consecutive filled cells + gaps appear in that row/column (e.g., '3 2 1' = 3 filled + gap + 2 filled + gap + 1 filled). Solving reveals a hidden pixel-art image (often depicting animals, objects, characters). Invented by Non Ishida (Japan) in 1987 as 'window art puzzle'; independently invented by Tetsuya Nishio around same time; popularised in Japanese newspapers 1988+ + Times of London 1990s. Nintendo Picross (Game Boy 1995, Super NES 1995) launched game-form popularity; ongoing Nintendo Picross series (Picross e, Picross S) on 3DS + Switch has 20+ entries. Web + mobile apps (Pixel Art, Picross Touch, Nonograms Katana) have millions of downloads. Standard sizes: 5×5 (beginner), 10×10, 15×15, 20×20 (advanced), 30×30+ (expert). Color Picross variants use multiple ink colors. Solving is pure deductive logic (no guessing needed for well-formed puzzles). Speed-solving competition exists (Nonogram World Championships since ~2010, though less formalised than sudoku).
Quick facts
Category
Puzzle Games
Type
Individual
Players
1–1
Duration
~30 min
Where played
indoor
Country of origin
🇯🇵 Japan
Estimated origin
Invented 1987 by Non Ishida + independently Tetsuya Nishio; popularised via Japanese newspapers 1988; Nintendo Picross 1995
Olympic
No
Popularity
regional
How it works
Objective
Fill grid cells based on edge clues to reveal hidden pixel-art image.
Match structure
Solve puzzle; puzzle is complete when all cells correctly filled/emptied.
Rules
Basic rules
Row/column edge clues
Numbers at row/column edges = counts of consecutive filled cells (gaps between counts = at least 1 empty cell).
Fill or X-mark each cell
Each cell is either filled (part of image) or empty (X-marked for clarity).
Solution must satisfy all row + column clues
Every row + column must match its clue exactly for solve to be valid.
Advanced rules
Well-formed puzzles have unique solution via pure logic
No guessing needed — every step can be deduced. Puzzles with multiple solutions are considered mal-formed.
Color Picross variants
Some puzzles use multiple ink colors; clues include color indicators.
Speed-solving techniques
Advanced solvers use 'edge-of-clue' deduction, 'sum-of-clues' overlap detection, and 'no-space' contradiction patterns.
Scoring
Puzzle complete = win; time tracked for competitive.
| Action | Points |
|---|---|
| Puzzle solved | 1 puzzle complete + time recorded |
Win condition · All cells correctly filled per clues.
Equipment
Puzzle grid + clues
Paper/digital grid with row + column clues at edges.
Pen / pencil / digital app
Fill cells (black) + mark empty cells (X).
Positions & roles
Picross Solver
×1Solo puzzle-solver.
Officiating
No standing officials; WPF-verified for competitive events.
- None (self-contained puzzle); World Puzzle Federation officials for WPC-adjacent Nonogram events
Penalties & fouls
Penalties
Incorrect cell fill (competitive)
Time penalty per mistake; some apps allow mistakes with penalty, others invalidate solve.
Timeout (competitive)
Unsolved after time limit = DNF.
Strategies
Start with longest clues
Long clues force overlap → guaranteed filled cells in row.
Sum-of-clues + gaps calculation
If sum of clues + minimum gaps = row length, all cells forced.
Edge deduction
Cells at edges near clue start often forced fill/empty based on adjacent constraints.
Terminology
- Clue (row/column)
- Numbers at edge indicating consecutive fill counts
- Filled / Empty cell
- Part of pixel image / not part
- X-mark
- Marker for definitely-empty cell
- Overlap
- Cells guaranteed filled by clue-length overlap in row/column
- Well-formed puzzle
- Puzzle with unique logical solution
Major competitions
World Puzzle Championship — Nonogram events
annual · worldwide · since 1992
Nintendo Picross official Time Attack modes (in-game)
ongoing · global (Nintendo platforms) · since 1995
Where it is played
Governing bodies
World Puzzle Federation (WPF, sponsors Nonogram at WPC)
Founded 1999 · Netherlands
Famous names & records
Famous athletes
- Non Ishida (JP, inventor)
- Tetsuya Nishio (JP, independent inventor)
- Top WPC Nonogram medallists
Records
Invented 1987 by Non Ishida
Non Ishida — Non Ishida invented Picross concept 1987 in Japan; published in newspapers 1988 (1987)
Nintendo Picross 1995 (Game Boy)
Nintendo — Mario's Picross (1995 Game Boy) launched Nintendo's ongoing Picross game series (1995)
Nintendo Picross e/S series 20+ entries
Jupiter Corp — 20+ Picross entries across DS/3DS/Switch since 2009 (Picross DS through Picross S9+) (2024)
Learn this sport
beginner
- 1
5×5 puzzles
Learn basic clue-following on simple pixel art.
intermediate
- 1
15×15 with overlap deductions
Master overlap + sum-of-clues techniques.
advanced
- 1
30×30 + WPC-level speed-solving
Expert-size puzzles + competitive speed.
Frequently asked
What is the difference between Picross and Nonogram?+
They're the same puzzle. 'Picross' is Nintendo's branded name (Picture Cross). 'Nonogram' is the international academic/community name. 'Griddler', 'Hanjie', 'Paint by Numbers' are regional variants — all identical puzzle.
Are Picross puzzles solvable by pure logic?+
Well-formed puzzles yes — every step can be deduced logically without guessing. Mal-formed puzzles (multiple solutions) exist but are considered poor design. Most published + Nintendo Picross puzzles are guaranteed unique-solution logic.
Sources & provenance
- Wikipedia — Nonogram— Wikipedia