SUDOKU
BeginnerUsefulness: High

Cross-Hatching

Disciplined scanning aimed at one box: use the rows and columns crossing it to eliminate cells until a digit has exactly one home.

Rows and columns carrying a 3 slice through the box, leaving one legal cell.

patterneliminatesolved

How to spot it

  1. 1Focus on a single box and a single digit.
  2. 2Draw lines from that digit's occurrences in the intersecting rows and columns.
  3. 3Whatever cell survives the crossfire is the placement.

When to use

When a box is nearly full — cross-hatching finishes it fast and cleanly.

Common mistake

Jumping between boxes mid-scan. Finish one box before moving on to keep your search organised.