Killer Pairs - Sounds good, but what are they?

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mhparker
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Killer Pairs - Sounds good, but what are they?

Post by mhparker »

I'm having difficulty finding out exactly what a "killer pair" is. I've searched for the term (together with "sudoku") on Google, but one gets surprisingly few hits, and sifting through those mostly takes you to references found in walkthroughs on this site. There's also nothing in Sudopedia on this.

Any help here would be much appreciated!
Cheers,
Mike
mhparker
Grandmaster
Grandmaster
Posts: 345
Joined: Sat Jan 20, 2007 10:47 pm
Location: Germany

Post by mhparker »

Finally managed to find the answer. It's basically an extension of the well-known "naked pair" technique for normal Sudoku. That is, if two cages (or one cage and a single cell) within a "house" (row, column or nonet) must contain either the value A or B, then these candidates can be removed from all other cells within the house.

JC's got a good description, see "Killer Naked Subset Removal" under:

http://jcbonsai.free.fr/sudoku/JSudokuU ... lvers.html

Unfortunately, JC's page doesn't use the abbreviate phrase "killer pair" like SumoCue does, which explains why Google didn't find it.
Cheers,
Mike
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