Proven Sudoku
Techniques / Almost locked sets
Sue de Coq (extended)
Also called Extended Sue de Coq, SDC extended, Doubly linked Sue de Coq.
New to this shorthand? How to read a sudoku grid explains r4c7, houses, candidates and the rest.
What it means
The same counting trick with more squares involved. The idea does not change, there is just more to count.
The exact rule, for stronger players
The rule, stated exactly: Sue de Coq where the intersection carries more candidates than cells, or where both flanking sets are doubly linked, producing additional eliminations.
What it removes: As for Sue de Coq, with additional eliminations inside the flanking sets when doubly linked.
Why it works: The same counting argument with a larger intersection set, or with the link running both ways.
Worked examples
None yet. This pattern does not turn up in our daily boards, so there is no real example to show. We would rather wait than draw a fake one.
Learn these first
- Sue de CoqLook where a row or column crosses a box.
Related almost-locked sets
- Aligned Pair ExclusionLook at two squares together and list every pair of digits they could hold.
- Aligned Triple ExclusionLook at three squares together and list every set of three numbers they could hold.
- Almost Hidden SetThe mirror image of an almost locked set.
- Almost Locked CandidatesTwo areas cross.
- Almost Locked SetA small group of squares holding exactly one number more than there are squares.
How often does it come up?
Our rough estimate: rare.