Rules & solving guide
How to play Color Sudoku.
Classic Sudoku has never been about math. Color Sudoku replaces digits 1 through 9 with nine distinct colors, turning logic into visual pattern deduction.
The Three Golden Rules
The puzzle consists of a standard 9×9 grid (81 cells) divided into nine 3×3 square regions. Puzzles begin with clues already placed on the board. Your goal is to fill the remaining cells following three exact constraints:
Every Row
Each of the nine horizontal rows must contain all nine colors once. No color can repeat in the same row.
Every Column
Each of the nine vertical columns must contain all nine colors once. No color can repeat in the same column.
Every 3×3 Box
Each of the nine 3×3 sub-grids must contain all nine colors once. No color can repeat within a box.
The Nine Colors
Each color represents a unique value equivalent to the numbers 1 through 9 in numerical Sudoku:
Because there is no numerical order (red is not "smaller" than blue), your brain recognizes patterns and clusters directly rather than calculating values.
Essential Solving Strategies
1. The Naked Single (Sole Candidate)
Look at an empty cell. Check its row, column, and 3×3 box. If eight of the nine colors are already present across those three intersecting groups, the cell can only contain the ninth remaining color.
2. The Hidden Single
Choose a color (for example, teal) and scan a 3×3 box. Even if several cells in the box are empty, other rows and columns may already contain teal and "cross out" all but one cell in that box. That remaining cell must be teal.
3. Candidate Notes (Pencil Marks)
On Hard, Expert, and Evil difficulties, you will rarely find immediate single placements. Tap the Notes button to pencil in multiple candidate colors in an empty cell. When you confirm a color in a connected row, column, or box, Color Sudoku automatically cleans up conflicting notes.
Colorblind-Safe Gameplay
Good game design should be accessible to everyone. Color Sudoku includes two dedicated systems for players with color vision deficiency:
- Symbol Overlays: In settings, turn on symbol overlays to give every color an embossed geometric shape (circle, triangle, diamond, star, square, etc.). Color is never the only way to identify a piece.
- High-Contrast Palette: Switch to the curated Contrast palette designed for maximum luminance contrast across protanopia, deuteranopia, and tritanopia.
Ready to play?
Color Sudoku is available now on the App Store for iPhone and iPad with 100% offline play, five difficulty levels, and no ads or accounts.
