There is no doubt, in my mind, that Takeda was among the pre-eminent, if not THE preeminent practitioners of "aiki" in the turn of the century. My qualifier is that there were surely others, who were much more secretive/cloistered, etc., among various koryu - who didn't demonstrate publicly. (Consider, for example, the incredible skills of Kuroda Tetsuzan, which were reportedly also held by his grandfather and others in the family of previous generations). Similarly Kunii Zen'ya of Kashima Shin-ryu in a later era. I certainly am not in the LARPer position of trying to speculate which long dead man was better than which, given I've never even seen them. And we can't judge the skills of such people by their followers, something Dan has noted in his scathing comments about some DR and aikido practitioners who put their miracles up on YouTube. I'll never forget the first time I saw a film of one of Sagawa's "leading students"!!!!! If I were to judge Sagawa based on that, I'd take up gymkata instead. So if would definitely be wrong to assert that because Yagyu Shingan-ryu shihan went to Takeda to learn (they did), that YSR never had such skills within their own curriculum, just that they very likely were lost or abandoned.
The evidence, however, for Takeda's pre-eminence (and later, Ueshiba's "near" pre-eminence - Sagawa keeping to himself, and Horikawa living in the middle of nowhere) - is the astonishment they created among nearly all their contemporaries. Furthermore, Takeda, as I've written, focused on a "gokui of gokui," so to speak - a philosopher's stone, a universal solvent, that was reactive with any element, as opposed to a usual gokui, which was a capstone to a specific body of knowledge, albeit with greater applicability that that one specific. Honestly, that is, in my opinion, Takeda's greatest genius. Or, as UEshiba is quoted as saying, "In aiki, we do it this way."
Part of my thesis, however, is that such skills were much more widely disseminated in previous generations. The founder of Tenjin Shinyo-ryu is described in terms much like the aiki masters and the ryu had internal training - which is hardly practiced. Same with Takeda's friends/elders who did Yoshin-ryu. So many ryu have similar accounts. Here's yet another I noticed, in an interview with the recently and sadly deceased Laszlo Abel:
Toshimitsu Masaki was bom in 1688 and I think he was like Morihei Ueshiba Sensei and Sokaku Takeda Sensei, who were reputed to be able to control the "ki" force that surrounded them. I found a lot of information about Masaki Sensei's duels. He almost never used weapons, relying only his hands. He actually fought one against a sumo wrestler, Goroji Ayakawa. He allowed the wrestler to do tsuppari (sumo style thrusting) against him, but the sumo man couldn't budge Masaki because of his strong control of his ki. And when Masaki did the same, the sumo wrestler went flying through the air.
(I'm not interested in how Laszlo tried to explain it - "ki force" - but the description of the actions of Masaki.
As for my thesis re Takeda - as before, I shan't rewrite my own book. But here's what I mean regarding Takeda's refinement, based on my own recent experience. The obvious caveat is that let us put Takeda at a number 12 on a scale of ten, and me, by my own estimation at a 1.347. But having done a little basic training, I start doing this or that technique in either Araki-ryu or Toda-ha Buko-ryu, and my body seems to say, "Well, why not do it this way," in essence, applying the "aiki" into the weapon's technique, without changing the external form in the least. This reverberates back into my basic training, which leads to new, "why not do it this way" experiences. They build on each other - perhaps this reverberation is the meaning of Ueshiba's affection for the word, "Yamabiko" - mountain echoes - or I may be just playing with words here.
Now, consider Takeda, with his exponentially greater skills than mine. Not only does he/his body recognize opportunities at ANY moment to do things with aiki, he surely encountered many different schools that had at least remnants of such training within their own curriculum. (Jikishin Kage-ryu being one, and I've recently found, Hokushin Itto-ryu under Chiba Shusaku, the main Tokyo rival of the Jikishin Kage-ryu, with whom there were many friendly competitions). In other words, imagine a skilled engineer finding a machine that is rusted and jammed, one he didn't make himself with somewhat different technology. But with a very little work and a little oiling, he's got it running again.
I therefore see Takeda - remember a mere teenager hitting the big city and going buck-wild, so to speak. With an educated body meeting bodies of knowledge, he educated himself all the further.
As for Dan's ideas on Oshiki-uchi, I've dealt with the limitations of the gokui idea in my book, that it's not something, to date, that is associated with any ryu, there are no independent historical accounts of such practices, and all the claims suggest an "Aizu-wide gokui" disseminated throughout a social class, beyond any one family, by the way, that somehow is never mentioned in any records whatsoever. In other words, it was allegedly too widely spread to be unmentioned or secret. (Again, gokui are not secret in the sense of hidden knowledge - it's always HIPS - but they a) aren't explained, b) aren't practiced. (Witness Jigen-ryu's gokui - "Dragonfly on a post" that I discussed a long time ago on e-budo).
Anyway, it's a moot discussion point barring further research. The Nishinkan still exists (that's the Aizu-han school). The question is if records lie mouldering, as they do in so many other areas. I was recently at the Odawara Library going through the Fujita Seiko collection of martial arts documents. This is publicly accessible and open to anyone who makes a phone call. Of the ten documents I reviewed, none had been looked at in the previous ten years.
It's very possible that there are documents just waiting for someone who is interested enough to look. Yes, I'm aware that all of this is the equivalent of trying to finish a jigsaw puzzle someone left on a table, but interesting, nonetheless.