Shortly after I first raised these questions, in 1978 or `79, I visited the dojo of the late Koichiro Yoshikawa, 64th headmaster of the Kashima Shinto-ryu. He very graciously answered many questions about the history and techniques of the ryu. Moreover, he showed me a registry of the people who had entered the Kashima Shinto-ryu and performed keppan (lit., "blood seal," signing the enrollment register and sealing it with one's own blood as an earnest of one's sincerity and serious intent) dating from before World War II. Guess what, sports fans? One of the names in the register was that of Morihei Ueshiba, along with that of Zenzaburo Akazawa, his deshi. I was told that a number of people at the Kobukan, including Ueshiba, studied for a period of several years. Once again, when I brought up the subject of Kashima Shinto-ryu and its influence on aikido, several aikido people, including one of the most senior instructors at the Aikikai, assured me I was mistaken. The only rejoinder I could make was that: a) I can read, and b) I saw the register with my own eyes (one can dispute with one's teachers and seniors in English without seeming impertinent, but it's almost impossible to do so in a Japanese context).
Ueshiba never studied KSR. He wanted his students to study while he watched. The soke made him take keppan, just to be allowed to watch. Most famous were him telling his students something like he would never do this or that...like KSR. "In Aiki we do it this way." There are several quotes, I just don't have access to my files right now.
Later, I mentioned all of this to Stan Pranin, publisher of Aiki News, and he has since established this and many other hitherto previously unpublished details of Morihei Ueshiba's training in the classical martial arts and the influence of the koryu upon the development of modern aikido. A great deal more work, however, remains to be done.
Not true either.
Stan (right here in his interview with Jun) Relegates Ueshiba's training to a short study under a 17 year old Judo shodan his dad hired, part time study over a few years time, traveling to a Yagyu Shingan dojo (something like 5 hours away) part time on weekends. and......
23 years in Daito ryu.