Proven Sudoku
Techniques / Exotic and rank-zero
Junior Exocet
Also called JE, Exocet, Junior Exocet pattern.
New to this shorthand? How to read a sudoku grid explains r4c7, houses, candidates and the rest.
What it means
Two squares act as a launcher and two more as the target. A small set of numbers can only travel from one to the other. Anything else in the target squares is out. Rare, and very strong.
The exact rule, for stronger players
The rule, stated exactly: Two base cells in one band, two target cells in the same band but different boxes, and a set of base digits. Each base digit, if true in a base cell, must appear in a target cell. Cover houses constrain where the digits may go, licensing eliminations in the targets and elsewhere.
What it removes: Remove non-base digits from the target cells, and apply the cover-house constraints to the companion cells.
Why it works: The base cells hold two of the base digits. Cross-line constraints force those digits into the target cells rather than anywhere else in the band, and the cover houses restrict the remaining placements.
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
- Rank TheoryA way to count a pattern.
- Complex Fish (rank framework)The fish idea, but boxes are allowed to join the rows and columns.
Related exotic and rank-zero
- Multi-Sector Locked SetsCount several rows, columns and boxes at once.
- Pattern Overlay MethodEvery digit has to land in one of a fixed set of shapes across the grid.
- Senior ExocetA bigger version of the Exocet pattern, with more squares acting as the target.
- SK LoopA ring of almost complete sets passing through the corners of a band and a stack.
- Table-Driven MethodsWork out ahead of time what follows from each single guess, and store it in a table.
How often does it come up?
Our rough estimate: rare, and largely confined to the hardest published puzzles. It is the signature technique of that class.