Faced with a changing post-war society Minaki Soke realised the need to refine the school's training methods. He retreated to the mountains in Kobe near the Fumon waterfall to meditate. Minaki taught that "Budo without the spirit of Buddha is heresy" meaning that a heart of mercy is the way to achieve the true budo otherwise one will fall into an evil path, and "that the development of budo requires creativity".
Although Minaki originally renamed his new style as Fumon Yoshin Ryu, he later renamed his school as Hontai Yoshin Ryu. For his new style Minaki selected the Hontai Yoshin Ryu-Takagi Ryu techniques that he regarded as being the most important and organised them into the katas of Gyaku no Kata, Nage no Kata, Oku no Kata and Tanto Dori no Kata. Also incuded in Hontai Yoshin Ryu are selected techniques from Kukishin Ryu Bojutsu (chobo & hanbo), Muto Ryu (kodachi, tanto dori & tachi dori), and finally Hontai Yoshin Ryu Iaijutsu which was developed in the 1990's by the 18th Soke, Inoue Tsuyoshi Munetoshi.
In 1982 (the 57th year of Showa) Minaki Soke divided the scrolls of Hontai Yoshin Ryu and Kukuishin Ryu Bojutsu, passing Kukishin Ryu to Matsuda Kyodo who was Soke for one day before passing the Soke title to Tanaka Fumon who is now the 19th Soke of Kukishin Ryu Bojutsu. Sensei Matsuda Kyodo is actively teaching Shindo Muso Ryu Jodo at the Imazu Budokai, which also serves as the Hontai Yoshin Ryu Sohonbu Dojo.
Minaki passed the Hontai Yoshin Ryu Soke title to Inoue Tsuyoshi Munetoshi and Yasumoto Sensei as a Menkyo Kaiden holder (full transmission license and permission to become independent). Yasumoto Sensei stayed with Hontai Yoshin Ryu and along with his close friend Kanazawa Akira they assisted Inoue Soke with the teaching of Hontai Yoshin Ryu.
Kanazawa Akira was listed as the Chief Instructor of Hontai Yoshin Ryu in the Imazu dojo and Yasumoto Sensei was listed as the International Chief Instructor of Hontai Yoshin Ryu.
During that time Inoue Soke also asked Yasumoto Sensei to teach the higher level jujutsu skills to his son Kyoichi Munenori Inoue and for twelve years the young Inoue was Yasumoto Sensei's uke.
One day on the path between Osaka and Kobe, a 15 to 20 strong gang assaulted and murdered a young woman who was returning home after spending days trying to find food for her children.
Minaki, upset by the incident and also that the police were unable to deal with the gang, decided to take action himself!
As Minaki walked alone along the path he probably looked like a very easy target as he was of slight build, however as the gang attacked Minaki struck them down one by one striking them with edge of his hand (shuto-ate). Once the remaining gang members fled there were eight lying dead.
After hearing about the incident, one of Minaki's students asked his teacher how he managed to kill the gang members without using weapons. Minaki walked away to return shortly afterwards with a flat stone which he then broke in half with the edge of his hand, a feat Minaki soke is said to have demonstrated only a few days before his death!