Double Crossover

In 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.

See Also

• Crossover
• Triangular Connection