Cage/Unit Overlap
If every live cage assignment puts a digit in its overlap with a house, that digit leaves the rest of the house.
How it works
- 1Take a cage crossing a box boundary and enumerate its live cell-by-cell assignments, not just its unordered sum sets.
- 2The cage still has possible cells on both sides, so ordinary Captured Candidates cannot claim the whole cage lies in this box.
- 3Yet every live assignment puts 8 somewhere among the cage cells inside the box; the outside portion never carries it.
- 4The box's 8 is therefore locked into that overlap. Strike 8 from every non-cage cell in the box.