How to play Rainbow Sudoku

Prismku is Sudoku with colors instead of numbers. Fill every empty tile so that no color repeats in any row or column — and on Easy, Hard and Expert boards, not inside any bold box either.

• Easy 4×4 — four colors, 2×2 boxes. Perfect warm-up.
• Medium 5×5 — a pure Latin square: rows and columns only.
• Hard 6×6 — six colors with 2×3 boxes.
• Expert 9×9 — the full spectrum, classic Sudoku rules.

Every puzzle has exactly one solution and can be solved with logic alone. The Daily puzzle is the same for everyone in the world — solve it, compare your time on the leaderboard, and share your result grid without spoilers. Turn on ◐ colorblind mode to add a symbol to every color.

Scoring: faster solves score higher; each hint costs 15 seconds and each clash 3 seconds.