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`v v v`

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

| b b . | . . . | . . . | b = base cell restricted to digits from [abc] or [abcd]

| . . . | / . . | t . . | t = target cell (at first will contain every base digit)

| . . . | t . . | / . . | / = companion empty cell unable to hold any base digit

*-------*-------*-------* v = cross line pointers

In reference to this pattern, a three step system for recognising one-band Exocets is:

1: Find two base cells in a mini-line.

2: Look for two companion empty cells in the other two boxes in the two other lines.

3: Check that in the 3 cross lines each base digit is confined to 2 rows in the 2 parallel bands.

When this pattern is found, the two target cells will eventually reduce to different base digits making non-member digits false in these cells. Later, when a digit is assigned to either target cell, the cross lines will contain a Swordfish for that digit.

This search method works at any puzzle solving stage, but relying on the target cells to hold all the base digits will fail if one of them has previously been eliminated.

Theoretically there are two corollaries:

1: A digit eliminated from both the target cells must be false in the base cells.

2: A pair of digits excluded from the same target cell cannot both be true in the base cells.

The chances of either of these circumstances occurring in a puzzle requiring exotic patterns must be very small though.

Noting that the member digits of a one-band Exocet can't exist as givens elsewhere in the band can aid searching. It also severely reduces the chances of finding a double Exocet with different members.

There may also be prospects for finding Almost Exocets where one of the required conditions is not quite satisfied.

DPB