Shinkendo is an art about Japanese swordmanship. Toshishiro Obata originally published a couple of books circa 20 yrs ago (The Naked Blade & Crimson Steel) which detailed some of the aspects of Toyama-ryu batto jutsu. Some yrs later, he organized the Shinkendo system, which, as best as I can determine, built upon the knowledge he had dispersed in his earlier books. Shinkendo is now a very widespread system with licensed instructors in many places around the world. Their website is https://www.shinkendo.com. My school encountered Sensei Obata many yrs ago, prior to Shinkendo, and learned some of his style then, primarily using his first book (The Naked Blade) as a basis. We encountered one of his licensed instructors under Shinkendo a few yrs ago, Paul Couch. Had Sensei Couch over for a seminar. The style is very interesting but the kind of committment they wanted (both financially and time wise) would have been difficult to maintain. We were not in a position to commit to them, with the limited time in our already busy schedules.
