Killer Pair
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Jump to navigationJump to searchA Killer Pair is a Killer Subset of size 2.
Naked Killer Pair
The cells R78C6 = 6 = {15} or {24}, i.e. they must contain either 1 or 2. They therefore form a naked pair in conjunction with the {12} in R3C6. This allows us to eliminate {12} for the rest of column 6, which means that R4C6 = 3.
Hidden Killer Pair
The candidates {12} of R5 are locked either in the cage 5/2 in R5C12 or in the cage 9/2 in R5C89. Neither the cage 5/2 nor the cage 9/2 may include both 1 and 2. Therefore each of these cages must include one of 1 or 2, which means the cage 9/2 in R5C89 = [81] or {27} and cannot have {36} nor {45}.
