Watanabe felt that Foster was a promising student and suggested that he study with Mamoru Yamamoto, later noted as founder of Yoshukai Karate[3] but then still affiliated with Tsuyoshi Chitose's Chito-ryu.
[2][9] At this time Hiroyuki Koda assumed directorship of the U.S. Yoshukai Karate Association (USYKA), remaining under the umbrella of Mamoru Yamamoto.
In the early nineties he relocated to Titusville, Florida, where he shared a hombu dojo (headquarters) for seven years with Aikido Sensei Tom Walker.
[10] Foster continued to instruct senior grades at his hombu dojo in Titusville until 2008, when he retired from active teaching for health reasons.
[9] Although specific wins are unclear, Chito-ryu and Black Belt Magazine sources list him as a United States kumite champion from 1966 through 1970.
[14] Due to Foster's success as a practitioner and instructor, Yoshukai International has established and maintains dojos all over the world, including the U.S., Canada, Puerto Rico, Germany, Latvia, Australia, New Zealand and South Africa.