Hello, Victor! And thanks for posting this.
Wow... talk about a walk down memory lane!
First... this isn't a "requirement" in any Uechi organization (that I know of). This is some choreography put together by Yonamine Sensei. It is significant in the way Freud's theory of psychosexual development was - mainly in that it was the first ever. There can only be one first, and Yonamine's the man! But like Freud's work, it's very easy to look back 30 years later and see how God-awful it was. Nevertheless... at the time many of us (including yours truly) were enthralled with it. We had nothing, so we ate it up the way my perpetually hungry Ridgeback will eat anything that's in a trash can.
Some Uechi instuctors - including yours truly - have choreographed our own Uechi Sanseiryu bunkai. I put one together about 4 years after that and demonstrated it with Bruce Hirabayashi. It was a slightly different format, being a continuous motion bunkai the way Shorei Kai Goju Ryu bunkai work. (The kata doer and kata recipient roles alternate between two people in a continuous motion format, with a response for every attack until an ippon at the end.) I only wish I had filmed it when Bruce and I put it together. It wasn't great... but it was fun the way a music jam session can be fun. We learned something from the effort, and then moved on from there.
This actually inspires me perhaps to put together a newer Sanseiryu bunkai, now that I'm comfortable with what many of the movements can be. Maybe some day soon.
Good stuff, Victor. Thanks again!