專修大學
In 1946, Kase was promoted to 1st "dan" in Shotokan karate. He began studying economics at Senshu University and, in 1949, became captain of the university's karate team. That same year, he attained the rank of 3rd "dan". He graduated from Senshu University in 1951. Kase joined the newly formed Japan Karate Association (JKA) with the aim of becoming a professional karate instructor, and would later become Chief Instructor for the European branch of the JKA. One of his duties in the JKA was to train instructors in "kumite" (sparring); amongst his students were Keinosuke Enoeda and Hiroshi Shirai. Following Funakoshi's death in 1957 and a subsequent division in the JKA, Kase maintained ties with both factions.