Yasumoto Soke is renowned for his skill in Jujutsu and his great interest in history and archeology. He has written much about the history of Shimane prefecture and their archaeological finds. He is also known for having one of Japan's largest collections of Ukiyo (woodblock prints) and Sho (calligraphy).
During Yasumoto Soke's time as a city official he taught weapons defence and disarming techniques to the police in Hyogo prefecture, and was invited by monks of the prefecture to teach Jujutsu at their temple.
Yasumoto Soke began his training with Minaki Saburoji at 26 years of age when he asked Minaki Soke to teach him and they opened a dojo at Yasumoto's house. Yasumoto also assisted Minaki Soke when he taught medical students with demonstrations of bone-setting (osteopathy).
He was also a direct student of Kanazawa Ichizu (who was the father of Yasumoto Soke's friend Kanazawa Akira) and Nakagawa sensei the Soke of Mugai Ryu Iai which Yasumoto studied to 6th Dan.
Yasumoto Soke received Menkyo Kaiden (full transmission license and permission to become independent) in Takagi Ryu and also became Menkyo Kaiden in Hontai Yoshin Ryu in 1982 at the time of the appointment of the 18th Soke Inoue Tsuyoshi Munetoshi.
Even though Yasumoto Soke was granted Menkyo Kaiden and free to be independant at the time that Inoue became Soke, he continued to assist Inoue Soke for many years as the Hontai Yoshin Ryu International Chief Instructor, and along with Hontai Yoshin Ryu Chief Instructor Kanazawa Akira, Yasumoto Sensei was one of the senior Jujutsu instructor at the Hontai Yoshin Ryu Sohonbu dojo, and upon request of Inoue Tsuyoshi Munetoshi, Yasumoto Sensei accepted Inoue's student (and son) Kyoichi as his student and personal uke, Yasumoto continued in Hontai Yoshin Ryu to support Inoue senior and teach his son Kyoichi Munenori Inoue the higher level Jujutsu skills for 12 years.
During this time the young Inoue made Yasumoto Sensei a hanbo that he still uses to this day. Yasumoto, along with the 18th Hontai Yoshin Ryu Soke, Inoue Munetoshi Inoue, were the last generation of direct students of Minaki Saburoji and Kanazawa Ichizu (as one of the most distinguished apprentices of the 16th Soke Kakuno Hachiheita, Kanazawa Ichizu was assigned to become the substitute sensei of Kakuno's dojo).
Yasumoto Soke is renowned worldwide for his skill in Jujutsu and martial arts and since March 1981 he has been one of the major influences on traditional Jujutsu in the West. For several years he was the main teacher of Hontai Yoshin Ryu throughout Europe, Scandinavia and the USA. For many western students Yasumoto sensei was their first Hontai Yoshin Ryu teacher.
Yasumoto Soke remains true to the teachings of Kanazawa Ichizu and Minaki Saburoji and in 1999 he named his branch of Hontai Yoshin Ryu-Takagi Ryu as Motoha Yoshin Ryu. The name Motoha refers to the "original" Takagi Ryu teachings of his teachers Kanazawa Sensei and Minaki Soke.