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Multi Color Wrap

When one color is contradicted by another color chain.

Explanation

If one color in a chain sees both colors of a separate chain, that color cannot be true because one of the other chain colors must be true. Every candidate with the contradicted color can be removed.

Multi Color Wrap example Sudoku board 4 6 7 2 5 8 1 5 7 3 8 6 8 9 1 4 7 2 8 3 2 5 1 3 5 4 6 1 8 1 2 4 8 7 6 3 9 6 4 9 9 3 8 4 2 5 4 1 6 2 9 3 8
An example board where Multi Color Wrap applies

Practice tip

After comparing two color clusters, check whether one cluster color sees both alternatives in the other cluster.

Example steps

  1. Choose one candidate and build two disconnected color chains.
  2. Find one color that sees both colors in the other chain.
  3. Remove that candidate from every cell with the impossible color.

Try this technique on a real puzzle.

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