Ted Ehara wrote:
The book is produced by the folks at www.kototamabooks.com
They sell other works by Nakazono Sensei, an aikido teacher and student of the founder.
While I have found Nakazono Sensei's works interesting objects of study, close reading makes it clear that some of the views he presents in his books depart significantly from the Founder's take on kototama.
When one looks closely at the underlying analysis presented by Nakazono Sensei, for the most part it seems to owe a heavy structural debt to a line of Sanskrit study that is primarily found in Shingon and Tendai Buddhism, with a heavy veneer of Japanese exceptionalism.
Nakazono Sensei is not alone in this characteristics, since kototama practice is working with the Japanese written syllabary, whose mythological creator was Kobo Daishi, and the syllabary is patterned after Sanskrit.
It is difficult to find someone qualified to teach this material either in or out of Japan, and finding quality instruction in Sanskrit, or Shingon & Tendai is more likely (though not necessarily easy), and more likely to be sound in and of itself.
At least, that's my story and I'm sticking to it.
Hope this helps,