Re: Kisshomaru as Interpretor of the Founder's Words
I suggest that you read The Secret Teachings of Aikido in concert with another recently published book by Kisshomaru Ueshiba, entitled The Art of Aikido: Principles and Essential Techniques. This, too, is a translation by John Stevens of a Japanese original work, entitled Aikido Shintei.
In some way, my experience has been different to yours. For the first ten years of my aikido life, I never studied anything about the Founder. His sayings, selected by Kisshomaru Ueshiba in his early book Aikido made very little sense, but I talked quite often with K Chiba about his life as a deshi. This is partly what made me decide to come to Japan: to learn Japanese so that I could study Morihei Ueshiba on his own terms, so to speak.
In this respect, I was making use of my previous training in the Classics. Aquinas wrote perceptive commentaries on Aristotle, which he read in Latin, translated from the Greek by the Arabs. And he was heavily biased, also. So I thought it best to start at the beginning and read Aristotle in Greek, which meant reading Plato and the Presocratics, also. Of course, you can benefit from reading Aristotle in English, but I think you need a commentary, if only to help you find your way. A complex text like his Metaphysics is very difficult to understand.
The most useful early texts for understanding O Sensei were the early Saito volumes and they were especially useful because they were written in Japanese and English. Then there was Budo Renshu, also in Japanese with an English translation. John Stevens published a translation of Budo and I was struck by the fact that the introduction to this work was almost identical to the introduction to Budo Renshu, but that the translations were quite different in style and tone.
My studies in Japanese coincided with teaching the Bible to Japanese students and I decided to study the early books of the Kojiki and Nihon Shoki, also, to see how they differed in the treatment of creation, sin, death etc. Having read Takemusu Aiki, I could easily see that O Sensei made much use of the Kojiki, but could also see that he quarried this work for material to suit his own view of the world and the place of aikido within it. In other words, for aikido the Kojiki has to be coupled with Deguchi's Reikai Monogatari, which O Sensei also read. The other thing to remember is that Oomoto is very eclectic in its thinking, so it is quite possible that Masakatsu agatsu katsu hayabi was given a 'western' 'individual' meaning of TRUE victory is SELF victory: victory of oneself in a quasi-moral sense, which the original phrase never had.
My time in Japan has enabled me to meet and know two people who played a major role in the development of postwar aikido: Kisshomaru Ueshiba and Shigenobu Okumura. In all the discussions I had with Doshu, I had the strong impression that he felt it his mission to practise and teach genuine aikido (not an imitation of some prewar original), but divorced as much as possible from the personal and private contributions of O Sensei himself. So the kamidama disappeared and the preoccupation with kotodama etc were removed or played down in importance. I think the war played a fundamental role in this.
Kisshomaru wrote two seminal technical works on aikido and also a detailed biography of the Founder. He allowed Stan Pranin of Aiki News to SUMMARIZE this material in English, not to publish it in its entirety. So it does not really contain Kisshomaru's actual statements. An 'authorized' English translation of this biography is in progress. On the other hand, the English translation of Takemusu Aiki, begun by Tanaka Sonoko of Aiki News has come to a halt and my speculation (open to correction) is that this is because the Ueshiba family wanted to keep the translation of such an important work 'in house'.
The material published as The Secret Teachings of Aikido are secret only because they are regarded as gokui. The material appeared in the early issues of the Aikikai's Aikido Shimbun (=newspaper), which was edited for many years by Sadateru Arikawa. It was Arikawa Sensei who told me that the material was extensively edited.