Grid technique · Beginner
Bijection Cascade
The moment you confirm one pairing, every other pairing that competes with it in the same row or column becomes impossible.
Why it works
Each subject holds exactly one item per category. A confirmed match uses up that subject's only slot, so everything else sharing the row or column is automatically ruled out.
Trigger
Any fresh yes-mark, in any mini-grid.
Common mistake
Placing the yes and stopping there, instead of sweeping the full row and column it sits in for the eliminations it forces.
Example
Once Mina/Baker is confirmed, every other job for Mina is crossed out, and every other person is crossed out of Baker, automatically, from that one mark.