Color Nonogram Rules and Solving Tips

September 15, 2026 · 3 min read

A color nonogram differs from the classic puzzle by a single rule, but that rule changes how you solve it. Here's the adjacency rule, the techniques it leads to, and a three-color puzzle you can solve on paper.

One difference from black and white

A color nonogram keeps every rule of the classic puzzle: each line's clue lists the runs of filled squares in that line, in order. The only difference is that every number has a color. The number's color tells you which color that run is filled with. Every example in this article was computed with the solver that checks Gridora's color levels.

The adjacency rule

In a black-and-white nonogram there is always at least one empty square between two runs. In a color nonogram this depends on color:

• Two runs of the same color must have at least one empty square between them.
• Two runs of different colors may touch with no gap at all.

The reason is simple: two touching runs of the same color would look like one long run. When the colors differ, the boundary is already visible. Compare two versions of the same clue. In a four-square row, 2 orange, 2 blue fits exactly and fixes the whole row:

2 orange, 2 orange doesn't fit in four squares at all; it needs a gap, so at least five. In five squares the row is again fully determined:

This has an important consequence: runs of different colors pack more tightly, so the overlap technique fixes more squares in color puzzles. We explain how overlap works in how to solve nonograms.

Solving a color puzzle

• Think about each color separately. Knowing a square is filled isn't enough; you need to know its color. Sometimes a square is certainly filled, but which of two colors it is only becomes clear from the crossing line.
• Rule out missing colors. A column whose clue has no blue tells you no square in that column can be blue, which directly narrows where a blue run can sit in each row.
• Count color changes. Since neighboring runs of different colors need no gap, only consecutive runs of the same color decide how many gaps a line needs.

Try it: 5×5, three colors

The puzzle below has exactly one solution and can be solved by logic alone. Draw an empty 5×5 grid on paper and work from the clues:

Color blindness and readability

If color alone carries information, the puzzle becomes unsolvable for anyone who has trouble telling colors apart. When Gridora generates color levels, every pair of colors in the palette is checked for a lightness difference of at least 18 units and a perceptual color difference of at least 30 units (on the CIELAB scale). On top of that, each color can carry its own symbol, so the puzzle stays solvable from the symbols alone.

Color puzzles are coming to Gridora in its next major update.