🖼️ How to play Nonogram or Picross (guide)
By Miguel Arechaga
The Nonogram, also called Picross or Japanese puzzle, is a logic puzzle where you fill in cells following number clues until a hidden image is revealed. If you like Sudoku, this one will hook you too. Here's how to solve it with logic, no guessing required.
What is a Nonogram?
You have a grid with numbers at the start of each row and column. Those numbers indicate the groups of consecutive cells that need to be filled in. When solved correctly, the filled cells form a picture.
How to read the clues and play
- The numbers for a row or column are the consecutive blocks to fill in, in that order. For example, "3 1" means a block of 3, a gap, and a block of 1.
- Left click: fill in or clear a cell. Right click: mark an ✕ where you're sure it stays empty.
- Cross-reference row and column information to deduce each cell.
- Press Check to validate your solution. Choose 5×5 (easy) or 10×10 (challenge) size.
Logic techniques without guessing
The most useful technique is overlap. If a clue is large relative to the row's width, some cells will always be filled no matter what. For example, in a row of 5 with a clue of "4", place the block flush left and then flush right: the cells that overlap in both positions are always filled.
The second big help is empty marks (✕). Every time you confirm a cell can't be filled, mark it: you shrink the remaining space, and that often forces another cell to be filled by elimination. Alternate between filling in certainties and ruling out impossibilities.
Quick tips
- Start with the biggest clues; they leave fewer possible positions.
- A row whose numbers plus the required gaps add up to exactly the row's width is fully determined.
- Never guess: if you can't deduce a cell, look for another one you can.
Nonogram is pure logic, like Sudoku but in pictures. With overlap and empty marks, you'll solve any board without relying on luck.
🏆 Time ranking
Nonogram has its own global ranking: each board size (5×5 and 10×10) has its own time leaderboard. Go to Ranking, the 🕹️ 1 Player tab, choose "Nonogram" from the dropdown, and compare your score with other players, synced to your account. For your result to count you need a free account on MundoSudoku (just a username and password, no email required): you can play without one, but without logging in your score won't be saved to the ranking.
