Multi-Coloring

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Multi-Coloring

What It Is

Multi-coloring extends coloring when chains are disjoint. Different color pairs mark separate chains of the same digit; interactions between groups yield eliminations when colors would conflict in a unit.

When to Use

Extreme puzzles where one color chain gives no wrap/trap; when a digit has multiple unconnected conjugate networks.

How to Apply (Step-by-Step)

  1. Color the first chain (blue/pink).
  2. Color a second disjoint chain with new colors (green/orange).
  3. Type 1: if different colors from different groups share a unit, one group’s opposite color must be true; eliminate cells seeing both opposites.
  4. Type 2: if a color sees the opposite color from another group, derive similar eliminations.
  5. Remove the digit where logic forbids it; re-scan.

If a red (group1) and green (group2) candidate of digit 1 share a box, either all red are false or all green are false; cells seeing both opposite colors lose digit 1.

See also

Scanning / Cross-Hatching Single Candidate (Naked Single) Single Position (Hidden Single) Naked Pairs / Triples / Quads Hidden Pairs / Triples / Quads Pointing Pairs / Triples (Locked Candidates Type 1) Box–Line Reduction (Locked Candidates Type 2) X-Wing Swordfish Jellyfish XY-Wing XYZ-Wing W-Wing Alternating Inference Chains (AICs) Forcing Chains / Forcing Nets Nishio Coloring Multi-Coloring Uniqueness Techniques (Unique Rectangle etc.) Fish Variants (Finned X-Wing, Sashimi etc.) ALS Techniques (ALS-XZ, ALS Chains) Sue de Coq Pattern Overlay / Template Method
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