# Double Crossover

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Jump to navigationJump to searchIn Sudoku-X, the **double crossover** solving technique can be stated as follows:

- Consider a digit
**X**. Suppose the leading diagonal contains only two cells that has**X**as a candidate, call them**A**and**B**. Suppose the non-leading diagonal contains only two cells that has**X**as a candidate, call them**C**and**D**. If**A**and**C**are peers, then we can eliminate**X**from any cell that is seen by both**B**and**D**.

The double crossover technique can be replicated using Color Wing with two clusters, or by using the following chain:

(X): B = A - C = D

Double crossover is a special case of Triangular Connection.