Sudoku Luna
ExpertChains and uniqueness

Practise: Multi-Coloring

This verified teaching position begins directly with a real Multi-Coloring pattern. Follow the chain, inspect the candidates and make the deduction before you continue.

You are at the verified key position. Use a hint to follow the chain link by link when you need support.

Practice
Mistakes0Score3,500Time0:00

How to spot it

Build two separate strong-link colour chains for one digit. Keep the components separate: do not join them merely because cells see each other. Then look for equally coloured cells, one from each component, that see each other. Finally check outside candidates of the same digit that see all opposite-colour cells in both components.

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Where you will meet it

Expert grids are the only place this pattern regularly decides the solve. Bring your notes.

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