Much of the information about the kendō kata is based on the teachings of the late Inoue Yoshihiko-hanshi, mainly as related on the now-defunct blog はくどー庵 (Hakudō-an), by Sasaki Hiroshi-sensei, erstwhile columnist for the Kendō Nippon magazine and nitō wielder extraordinaire. Since that blog has been “under construction” since June 2023, and only the table of contents preserved in the Internet Archive, these articles are largely written from memory. If anyone has access to the articles on kendō kata by Hakudō-an, I would be very grateful to be able to read them again.
The official manual (Japanese)