Imaizumi sensei first started training in aikido in April 1959 during his days as a student at Waseda University in Tokyo.
During that time in spring of 1972 he was instructed by Tohei, who was still serving as head instructor at the Hombu Dojo, to travel to Los Angeles in the United States to teach aikido and ki-principles under Roderick Kobayashi Sensei, who was the chief Instructor of the Western States Aikido Federation at this time.
Before this, however, he would first accompany Tohei on a tour of the US new Ki-aikido dojos, more specifically in the Honolulu, Chicago, Philadelphia (and finally) New York regions.
On June 1, 1980, he was officially assigned the post of Chief Instructor for the Ki Society in the United States for a period of three years.
In September 1987, Imaizumi resigned from the Ki no Kenkyukai and martial arts in general, in order help with the management of the family business.
Many of these students, scattered around the US in New Mexico, New York and Texas, had by now left the Ki no Kenkyukai and founded their own independent dojos throughout the US.
He did not return to his old position in New York, but assembled a group of independent ki-aikido dojos under a new organisation called Shin-Budo Kai.