Erick - there is NO evidence whatsoever that either Nakai or Tsuboi ever had any experience with Yagyu Shinkage-ryu. None. ... Equally implausible is that Ueshiba's Yagyu Shingan-ryu teacher had a secret Yagyu Shinkage-ryu certificate
OK. calm down a moment and read what I said. Nakai (ca. 1904-1908) trained Ueshiba in Shingan. I didn't say he had a scroll in Shinkage, I said that Nakai is said to have had some Shinkage training
also. Otsubo noted it as being Shinkage when Kisshomaru remembers him coming regularly the their house (as you yourself have pointed out
. There are still places training with those arts together as descended from both Nakai and Otsubo
so this is hardly a specious association.
His period with Gejo -- Tomiki supposedly studied Shinkage with Ueshiba under Gejo -- thus it would have been after 1926 or later in the twenties after they met.
So Ueshiba Morihei could NOT be speaking of his kenjutsu training with Gejo at the time of his first vision of aiki in ~1923
(he was "forty years old" according to his own account).. His vision then was that "The form of budo must be love. One should live in love. This is aikido and this is the old form of the posture in kenjutsu."
This was the point and context of my original enquiry into this matter back in 2006.
He is not then speaking of his Shinkage training with Gejo which he has yet to start. He is unlikely to be speaking of Shingan which is a newer form (ca. 1600) than Shinkage (before 1560's), and descended from it. There may be something else that qualifies as "the old form" in kenjutsu but Shinkage is the presumptive claimant for the Meiji period and after.
He obviously had to know something of Shinkage to be recognized as such by Otsubo -- but to square that with the timing of his vision of the "old form" in 1923 -- the vision may have actually prompted dusting off his older (and likely more informal) Shinkage legacy by resuming training in it with Gejo thereafter, with Tomiki, sometime after they met in 1926.
Thus, some significant Shinkage training very likely predated his training with Gejo. If not Nakai, where? Nothing else makes as much sense of the timeline.