Simple Coloring

Level 5 · Orange Belt

Strategy:

Requires:

Learn after:

Medusa Coloring Remote Pairs X-Chain X-Cycles

Overview

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.

How It Works

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

Example

Look for Simple Coloring.

Sudoku grid showing the initial puzzle state for Look for Simple Coloring.

1

Simple Coloring

Build a coloring chain for digit 3 by following conjugate pairs.

Sudoku grid illustrating step 1: Simple Coloring — Build a coloring chain for digit 3 by following conjugate pairs.

2

Simple Coloring

Each link alternates color: exactly one color is TRUE, the other is FALSE.

Sudoku grid illustrating step 2: Simple Coloring — Each link alternates color: exactly one color is TRUE, the other is FALSE.

3

Simple Coloring

Find uncolored cells that can see cells of BOTH colors.

Sudoku grid illustrating step 3: Simple Coloring — Find uncolored cells that can see cells of BOTH colors.

4

Simple Coloring

One color must be TRUE, so every highlighted cell already sees a true 3 somewhere in the chain.

Sudoku grid illustrating step 4: Simple Coloring — One color must be TRUE, so every highlighted cell already sees a true 3 somewhere in the chain.

5

Simple Coloring

Remove 3 from the cells that see both colors: r3c8.

Sudoku grid illustrating step 5: Simple Coloring — Remove 3 from the cells that see both colors: r3c8.

6

Result after applying the technique.

Sudoku grid showing the result after applying the technique

Tips & Patterns

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.