 At the age of 17, Kuniba started learning Mugai Ryu Iaido from Ishii Gogetsu, a practitioner of Mugai Ryu, himself a student of Nakagawa Shiryo Shinichi, 11th and last headmaster of Mugai Ryu.Kuniba proceeded to practice Mugai Ryu for the next 40 years.However, the style of Mugai Ryu, as taught by Ishii Gogetsu and then modified by Kuniba is sufficiently different from other branches of Mugai Ryu (Mugai Ryu splintered with the death of the Nakagawa, so no single orthodox line exists), that this branch of Mugai Ryu is commonly known as Kuniba Ryu.