Just really started playing a couple of days ago, and have been reading through some of the strategy sites (mostly Simes' and Angus'), and became quite curious as to why there is a special mention of Swordfish at all, as it appears to be simply a special case of what would be a "3x3 X-Wing" (that is, if three rows/columns each have their only candidates for a given digit in the same three columns/rows, then all additional candidates for this digit in these columns/rows can be eliminated).

We can easily weaken our conditions in the above by just requiring there to be three columns/rows which capture all candidates for this digit in these rows/columns (ie, you don't necessarily get a complete 3x3 grid of candidates, but a 3x3 grid of candidates and possibly empty spaces).

Given this extension, "Swordfish" is obviously just a special case.

Just curious if the specific "Swordfish" position shows up frequently enough to warrant special mention.

Thanks.