Platon Sudoku · Sudoku Study

Multi-Coloring · Step-by-step example

Two separate coloring components for one digit each have opposite A/B states. A candidate from each component sees the other, creating a cross-component conflict. Remove the digit from a target that sees a candidate in each opposite alternative.

This course is adapted from Platon Sudoku App. Read the complete example here, then continue learning and practising in the app.

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Recognize the pattern

Two separate coloring components for one digit each have opposite A/B states. A candidate from each component sees the other, creating a cross-component conflict.

How to find it

Build two separate strong-link networks, mark their A/B states, and find candidates from different components that see each other.

What it allows

Remove the digit from a target that sees a candidate in each opposite alternative.

Avoid the mix-up

Do not merge the two components into one color chain. Verify each component’s strong links and the target’s sight of both alternatives.

Step-by-step example · Two components

This example starts from a saved intermediate position. Its candidates include earlier logical eliminations; they are not fresh automatic notes.

Blue: evidence. Green: conclusion. Crossed-out digits: eliminated candidates. R1C1 means row 1, column 1.

Step 1 · This is Multi Coloring

This walkthrough covers HoDoKu Multi Colors Type 1: two colored components contain a cross-component conflict. Candidate 6 forms those two separate coloring components. Within each component, round A and square B are opposite states. Keep the target R7C2=6 in view.

Step 2 · Inspect component 1

Coloring component 1: round A = R2C2=6; square B = R2C4=6. A and B are opposite states, and every strong link joins them within this component.

Step 3 · Inspect component 2

Coloring component 2: round A = R3C5=6; square B = R7C5=6. A and B are opposite states, and every strong link joins them within this component.

Step 4 · Find a cross-component conflict

R2C4=6 and R3C5=6 belong to different components but see each other in box 2. They cannot both be true.

Step 5 · At least one opposite state is true

Since the conflicting states cannot both be true, at least one opposite state—R2C2=6 or R7C5=6—must be true.

Step 6 · The target sees both alternatives

R7C2=6 sees R2C2=6 and R7C5=6. Whichever opposite state is true excludes the target.

Step 7 · Remove the target candidate

Remove R7C2=6.

What it allows

Remove R7C2=6.

Multi-Coloring · Remove the digit from a target that sees a candidate in each opposite alternative.

Practice

This course is adapted from Platon Sudoku App. Read the complete example here, then continue learning and practising in the app.

View on Google Play

Recognize the pattern

How to find it

What it allows

Avoid the mix-up

Step-by-step example · Two components

What it allows

Lesson directory

Practice