Grouped Discontinuous Nice Loop
Treat candidate groups as loop nodes and use the contradiction at the discontinuity to derive an elimination.
All candidates have been entered in the empty cells.
A and B mark the two ends of the chain. Assume A is false. On a solid link, one false end makes the other end true. On a dashed link, one true end makes the other end false. Apply these rules from A to B in link order. Under this assumption, B is true. Including the case where A is true, at least one of A and B is true. Candidate 1 marked × can be removed.