Ohsaki Jun Sensei was born in Tokyo. In 1990, he began studying Japanese yoga and martial arts at the Sennin Foundation Center. He received Shihan-Dai ("Associate Instructor") teaching certification in Shin-shin-toitsu-do (Japanese yoga), and a Koshi ("Lecturer") certificate from the International Japanese Yoga Association in Kyoto.
He holds a menkyo shodan teaching license in Saigo Ryu martial arts. He serves on the Board of Advisors for the Shudokan Martial Arts Association and has appeared in martial arts demonstrations in Japan.
He has studied shodo (classical brush writing) and sumi-e ("ink painting") at the Sennin Foundation Center for many years. His calligraphic art appeared in Brush Meditation: A Japanese Way to Mind & Body Harmony, and he also served as a model for many of the photos in this book. He received the rank of chuto in Ranseki Sho Juku shodo and the art name Junseki, both indicators of advanced proficiency.