Color Sudoku

Same logic, no numbers

Color Sudoku is ordinary Sudoku with the digits 1 to 9 swapped for nine colors: Red, Orange, Yellow, Green, Blue, Indigo, Violet, White, and Rainbow. Every row, every column, and every 3×3 box must contain each color exactly once — identical rules, so all the same logic and the same Hint button apply. Pick a color from the palette, then tap a square.

Built to be playable for everyone

The board is pure color by default. Color-only puzzles are hard for the roughly 1 in 12 people with color-vision deficiency — and red and green, both in this set, are the classic hard-to-tell-apart pair. So there are three aids, all optional and stacking:

• Colorblind mode — the switch above the board swaps the palette for one drawn from the Okabe-Ito color set, chosen to stay distinguishable under red-green and blue-yellow color blindness, with varied lightness so the colors differ in brightness too. Your choice is remembered for next time.
• Labels on — overlays each color’s initial on every square; available in both palettes.
• The color key above stays on screen, and every square is named for screen readers.

You can also type the number keys 1–9 to place colors in the order shown in the legend.