Mark - As for what Sato said:, just for the record:
I do not believe that Sato had a hidden meaning
. . . Tanomo was such a high ranking councillor of the Aizu clan, I have doubts whether such a busy man could have inherited such a complex system of jujutsu . . . .I believe that Sokaku's father, Sokichi, thought it would be easier to teach the art to his eccentric son if such an important clan figure like Chief Councilor Tanomo Saigo was nominally in charge of the instruction of Daito-ryu
- But, I think your theory is as plausible as any other. Truly. For all we know, Tanomo taught Takeda how to walk in court settings, how to act formally, and elements of body skills were taught in such settings. And this turned on a light in that genius and he extrapolated it into his extant martial skills. All speculation - but that's as good a theory as any that I have.
I don't have anything more to contribute on this thread that I haven't said here or elsewhere, so I'm away.
It's not that he might have had a hidden meaning...he might have had complete ignorance of the subject.
How does "learning aiki" equate with a "complex system of jujutsu?"
I think it completely plausible that these guys didn't have a clue where Takeda got it from. If they really did...hell if Takeda really had something better to offer... we would have heard much better evidence than the wierd, out of place, things they have offered. It also fits in with their perplexed reactions to certain lines of questioning. How much did they know, versus the popular idea of lying and obfusaction as a Japanese norm to avoid revealing what they wanted you to know.
An example being the five questions Sato was given in a letter addressed to Ueshiba, the first of them being "Why are you lying about me?" Did Sato know anything about this or was he just a delivery boy?
What if certain stories were indeed the true ones.
Such as him learning from his dad and grandpa
Such as his learning other Koryu in his musa shugyo travels
That his growing skills and internal power were then magnified with learning aiki (maybe the tenants of IP/aiki from Saigo Tanamo
It explains other suggestions such as Takeda never repeating a technique because.... by and large "they weren't techniques yet."
What if certain private comments "That he was riffing with aiki, on the bodies of people and both he and his students were "recording the reactions" ....as waza. Waza that by and large is very weird compared to traditional koryu jujutsu and IMO (and as you well know is many many others as well) isn't of much use at all without aiki.
There are certain stories that make just as much, if not more plausible sense when pieced together that support both your theories of his grandfather and father, his koryu musa shugyo and his learning aiki from Tanamo. all rolled inot one complete whole. As such it can establish a framework for Daito Ryu being a modern invention based on aiki and supported by prior koryu body knowledge, tactical and practical experience.
All of which fits perfectly into "Hidden in Plain sight."
As you say what "turned-on the light in the mind of a certain young genius, and he extrapolated"...as opposed to what may have been laid out in explicit detail... we will never know.
All the best