Simple Coloring

Simple Coloring (Singles Chains) uses two colors to track conjugate pairs of a single digit. By alternating colors along chains, contradictions or eliminations can be found.

Technique

1. Find conjugate pairs for a digit (exactly 2 occurrences in a unit).
2. Color one cell, give the opposite color to its conjugate.
3. Continue coloring along all connected conjugate pairs.
4. Rule 1 (Color Wrap): Same color twice in a unit - that color is false.
5. Rule 2 (Color Trap): Uncolored cell sees both colors - eliminate that candidate.

Tips

• Start from any conjugate pair and alternate colors systematically.
• Either all cells of one color are true, or all cells of the other color are true.
• Color Trap is the most common elimination type.