And, if you don't mind enterig in the realms of wild speculation on the dancing idea, what could have Sokaku learned during his tour with a circus/vaudeville group. Could have he learned something while on tour with Lulu Hurst japanese equivalents, strongmen, acrobats, dancers, impoverished (but skilled) samurai accepting challenges from any comers and the like?
BTW, Ueshiba taught dancers too and I think I've read somewhere he awarded one a high rank,
We could be wildly speculative.
But, consider that among all of the things we know about Takeda, nowhere do we hear of Takeda being a liar. What does Sagawa say? He *believes* Takeda got aiki elsewhere because of studying a photo of Tanomo and some mention of not being a martial master. And then what does Sagawa say? He might have learned a little bit of the form only.
So, we, too, have Sagawa saying that he thinks all the "martial" skills were from others, but he also says that Tanomo might have taught Takeda something ... outside of martial mastery. Hmm ... oshiki uchi as the indoor disciple being taught some internal skills to enhance the martial skills (Again, with Takeda, these martial skills were both external and internal). Perhaps, the entirety of internal skills were not from Tanomo, but there are indications that something was taught. Something which Takeda defined as his "aiki" later on.
However, no one has ever introduced dancers.