It was a double wrist lock.
The catch fanboys aren’t just spewing pure hype. If you do a “kimura” the way that some catch guys teach it, it’s a compound attack that is a wrist lock, elbow lock, and shoulder lock at the same time. Depending on how they defend and where they’re flexible different arm parts will fail first. In this case the way the guy defended transferred the force into the shoulder.
The grip is harder to get than the kimura as typically taught in BJJ but it’s an even more devastating submission. Plus, if they fight out of the special grip, you’re basically just in a regular kimura so no real loss.
I go for it that way every time if I intend to try to finish the submission instead of using it as a back take/sweep/pass hold. Funny thing is that Rafa has started to use a similar grip in a lot of his kimura videos.
It *is* mechanically similar to the armlock you showed Rafa using from ura sankaku/rear triangle. You just add a wrist lock on top of it.
