Mirrored from **Sudopedia**, the Free Sudoku Reference Guide

A **conjugate pair** is a pair of candidates with a strong link. They are the last 2 candidates for a single digit in a house they share.

Different terms were introduced for the same concept when the Sudoku community developed their solving techniques. The term **conjugate pair** is mainly used in coloring techniques. The term **strong link** refers to the link between 2 candidates, but does not include the candidates themselves, whereas the term **conjugate pair** clearly refers to the candidates. Furthermore, a strong link can also exist between the last 2 candidates in a single cell, but it is not customary to call these 2 candidates a conjugate pair.

There is also a difference between a conjugate pair and a connected pair. In a **conjugate pair**, only one of the two candidates in the house can be true. In a **connected pair**, at least one of the candidates must be true, but it is also possible that both of them are true. The only certainty we have about a connected pair is that they cannot both be false at the same time.