Opinion & Commentary
The editorial voice of The Daily Nines
Gathering editorial voices...
The Puzzle Professor
Technique 1
Naked Pairs Technique
When two cells in a row, column, or box can only contain the same two numbers, those numbers can be eliminated from other cells.
Technique 2
Hidden Singles
If a number can only go in one cell within a row, column, or box, it must go there — even if that cell has other candidates.
Technique 3
The X-Wing Strategy
An advanced technique for eliminating candidates across rows and columns when a number appears in exactly two places in two different rows.