solving using "pairs only"

Advanced methods and approaches for solving Sudoku puzzles

solving using "pairs only"

Postby LittleBird » Fri Aug 12, 2005 2:32 am

Hi - I have been working on the puzzles appearing in The Times. For the past 10 days or so I have been solving the fiendish puzzles by only filling in units that have 2 possible numbers and no more.

If a unit has more than 2 possibilities I leave it blank.

I make notes in the margin when a column or row within a particular block is sure to contain a particular number. I also mark possible numbers if they appear only 2 times in any given block, even if they are not in the same column or the same row.

Has anyone else been solving their puzzles like this? I just solved No 282 using this technique.

For me, racking up numbers within units is very confusing. Now I'm seeing that in many cases it's possible to solve the fiends with only 2 numbers per unit.

The technique requires a lot of cross-checking the slicing-n-dicing, which is why I make the margin notes.

Can someone else try this and confirm? Am I just lucking out and the fiendish puzzles have not been extreme fiends lately?

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Joined: 11 August 2005

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