81 VERTICES · 810 EDGES · 9 COLORS
Sudoku, in nine colors.
Your puzzle. A real graph. Every decision, visible.
Enter any standard 9×9 Sudoku, or try an example.
Edit the clues, then solve.
Each dot is one cell. Connected cells must have different colors.
Paste a puzzle
Search settings
Exact search can take longer on difficult inputs. You can cancel at any time. A time limit never counts as proof that a puzzle is impossible. Replay retains the first 20,000 events; search continues if that recording limit is reached.
HOW IT WORKS
Nine colors.
One constraint.
A cell becomes a vertex. An edge connects two cells that share a row, column, or 3×3 box. Neighbors must have different colors. The clues are fixed colors.
The solver chooses the blank vertex with the most distinct colored neighbors, tries an available color, and backtracks when a branch fails. A complete coloring gives a solved Sudoku. The graph and grid replay those actual decisions.
Digits are color labels. The algorithm uses no arithmetic on them, no answer database, and no network solver. Diagonal, killer, and other Sudoku variants use different constraints and are outside this app’s scope.
The original animation
Download video ↗An actual solver trace, paced for viewing. 16 seconds is the animation’s length, not the time taken to compute the solution.