Here is a re-write of the revised pattern specifications:

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`*-------*-------*-------*`

| B B . | . . . | . . . | B = Base Cells

| . . . | Q . . | R . . |

| . . . | Q . . | R . . | Q = 1st Object Pair

*-------*-------*-------* R = 2nd Object Pair

| . . S | S . . | S . . |

| . . S | S . . | S . . | S = Cross-line Cells

| . . S | S . . | S . . |

*-------*-------*-------* . = Any candidates

| . . S | S . . | S . . |

| . . S | S . . | S . . |

| . . S | S . . | S . . |

*-------*-------*-------*

The different cell pairs occur in different boxes in the same band (the JExcoet band). The three cross-lines intersect this band as shown, passing through the object cell pairs but not the base cell pair.

Conditions:

1) The base cells must be restricted to a set of three or four digits (the base candidates)

2) Object pairs must have one cell that contains at least one base candidate (the target cell) and the other that contains none of them (the empty companion cell)

3) Outside the JExocet band each base digit should not be capable of occupying more than two of the cross-line cells in the solution. This is satisfied when all the occurrences of a digit in these external cells, including any that are given or solved, can be covered by no more than two lines.

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`Examples`

v v v

. . \ | \ . . | \ . . . . O | \ . . | O . . . . \ | \ . . | O . .

. . O | O . . | O . . < . . O | \ . . | O . . . . O | O . . | O . . <

. . \ | \ . . | \ . . . . O | \ . . | O . . . . \ | \ . . | O . .

. . \ | \ . . | \ . . . . O | \ . . | O . . . . \ | \ . . | O . .

. . O | O . . | O . . < . . O | \ . . | O . . . . \ | \ . . | O . .

. . \ | \ . . | \ . . . . O | \ . . | O . . . . \ | \ . . | O . .

2 Parallel lines (I) 2 Parallel Lines (II) 2 Orthogonal Lines

An Exocet start pattern satisfies conditions 1) and 2) and is used to identify base candidate sets to analyse further.

A Junior Exocet pattern satisfies all 3 conditions and proves that the two target cells will hold the same digits as the base pair. This allows any non-member candidates to be eliminated from these two cells.

The pattern is described by identifying the candidates in the base cells and the location of the two target cells

eg (abcd)JExocet:r1c12,r2c4,r3c7

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champagne firstly let me say how valuable your puzzle collections are as research material, so thank you very much.

Now that the number of patterns found has gone up, I would like to know how well your revised search routine implements each of these conditions.

Points of interest are target cells missing the full digit set and empty cells that aren't singles, as these changes would allow Exocet searches to be made at any time when solving a puzzle, not just at the start.

Do you intend to fully implement condition 3) ?

If you do, then it would be very useful if a representative sample of the hits found for conditions 1) and 2) could be extracted. The search could then be re-run with condition 3) also enabled to see what proportion of all Exocets are JExocets.

The same type of test could then be run to check what proportion of them have the two target cells in sight of each other.

Now finding an Exocet is one thing, but it is only successful when it proves that two cells must hold the same candidates as the base pair. So it would be interesting to discover the success rates achieved using different versions of these conditions.

DPB

[Edits]Specification revised according to various suggestions in later posts.