Most interesting. Thanks for the detailed answer.
I have an additional question. Have you got any idea if many other Japanese Ju-Jutsu styles are as similar, or are significantly less similar? (in this regard, the notion of correlation is very useful, when correlating signals, one often compares the correlation to a desired signal to the correlation to other signals).
I studied Takeda Ryu under Nakamura Hisashi in Japan at his home dojo about 20 years ago - got to Shodan. Many of the techniques were just like those of Aikido, albeit with different names, and they also had a very interesting system of Kokyu-nage. In fact, the way they organsied everything was very interesting - no time to write now.