How to read the grids
- Given - clues from the starting puzzle
- Subject - cells the technique focuses on
- Eliminated - candidates this technique removes
- Candidate - pencil marks shown for reference
How to spot it
Pick a digit. Build a graph of conjugate pairs. Color them alternately. If any cell sees both colors of the same digit, that cell cannot hold the digit. If two same-color cells share a unit, that color is false everywhere.
9
9
9
9
9
Worked example
For digit 9, blue cells and yellow cells form a conjugate chain. The highlighted red cell sees one of each color - it cannot be 9.
Time to practice
Reading is half the work. Try a puzzle now and look for the techniques you just learned.