Proven Sudoku
Techniques / Exotic and rank-zero
Domino Loop
Also called Domino loop pattern.
New to this shorthand? How to read a sudoku grid explains r4c7, houses, candidates and the rest.
What it means
A ring of pairs that lean on each other all the way round, like falling dominoes. Because the ring closes, each pair pins the next, and the whole ring is forced.
The exact rule, for stronger players
The rule, stated exactly: A loop of paired intersection regions closely related to the SK Loop, differing in the arrangement of the paired sectors.
What it removes: As for the SK Loop.
Why it works: Rank-zero counting around a closed loop of sectors.
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
- SK LoopA ring of almost complete sets passing through the corners of a band and a stack.
Related exotic and rank-zero
- Double ExocetTwo of those launcher patterns sharing the same numbers.
- FireworksA number is trapped so that it can only sit in one row, one column, or the square where they cross.
- Gurth's Symmetrical PlacementSome puzzles are built with a mirror pattern.
- Homogeneous ChainsA chain where every link is the same kind.
- Junior ExocetTwo squares act as a launcher and two more as the target.
How often does it come up?
Our rough estimate: rare. Sources differ on where the SK Loop ends and the Domino Loop begins.