sudokly
Intermediate · 6 techniques

Intermediate Sudoku Techniques

Pair and reduction techniques that crack hard puzzles.

  1. Naked Pairs
    A naked pair is two cells in the same row, column or 3x3 box that contain exactly the same two candidate digits.
  2. Hidden Pairs
    A hidden pair is two digits whose candidate locations within a row, column or 3x3 box are confined to the same two cells.
  3. Naked Triples
    A naked triple is three cells in the same row, column or box whose combined candidates are exactly three digits.
  4. Hidden Triples
    A hidden triple is three digits whose candidate locations within a row, column or box are confined to the same three cells.
  5. Pointing Pairs
    A pointing pair occurs when all the candidate cells for a digit within a 3x3 box lie in the same row or column.
  6. Box-Line Reduction
    Box-line reduction is the mirror of pointing pairs.