Proven Sudoku
Techniques / Single-digit patterns
Multi-Coloring
Also called Multicolouring, Multi-Colour, Extended Coloring.
New to this shorthand? How to read a sudoku grid explains r4c7, houses, candidates and the rest.
What it means
Colouring marks a digit's spots in two shades. One shade is right, one is wrong. Multi-colouring compares two of these chains. If a shade in one chain clashes with a shade in the other, every square that sees both loses the digit.
The exact rule, for stronger players
The rule, stated exactly: For digit d, color two or more distinct conjugate components. If a color of component X sees a color of component Y in such a way that both cannot be false, the resulting constraint eliminates d from cells seeing the implied true colors.
What it removes: Remove d from cells seeing both members of any pair of colors that cannot both be false.
Why it works: Each component contributes exactly one true color. Relations between components restrict which combinations are possible, and eliminations follow from combinations that are impossible.
Worked examples
None yet. This pattern does not turn up in our daily boards, so there is no real example to show. We would rather wait than draw a fake one.
Learn these first
- Simple ColoringPick a digit.
Related single-digit patterns
- SkyscraperPick a digit.
- Turbot FishPick one digit.
- X-ColoringColouring with an extra step.
- 2-String KitePick a digit.
- 3D MedusaColouring spread across every digit at once, not just one.
How often does it come up?
Our rough estimate: uncommon, and largely superseded in practice by AIC, which expresses the same deductions more flexibly.