I have always being intrigued about this. Where did Ueshiba O'Sensei learn the sword techniques that were to be called Aikiken? Until now, the official history establishes that all Aikido was the genial creation of O'Sensei, that he created everything. It's often denied even that the hand arts, the taijutsu, is based on Daito Ryu Aikijujutsu. As always, there is one "official history" and one "real history".
The following is an extract from Koryu.com, written by Meik Skoss:
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.
There is, thus, evidence that Ueshiba O'Sensei studied Kashima Shinto Ryu, and the trained eye can see similarities in Kashima Shinto Ryu waza with Aikiken waza. For example, Kashima Shinto Ryu's "ichi no tachi" is virtually identical to Aikiken's "ichi no kumitachi" as taught by the late Morihiro Saito Sensei.
Of course, Ueshiba, being the genius he was, was no content with just preserving what he learnt from the school, but modified it to adapt to the concept of Aiki. The following video from a Kashima Shinto Ryu exhibition is an ilustration of this point.
While one can see similar techniques here and there, it is obvious that the kata are not only not identical to those of the Aikiken, but also the intention is different.
More to come on this subject... maybe tomorrow.