Afterwards, Tashima studied from 1983 to 1986 at the German Sport University Cologne and received a B coaching license. As he returned, he was a technical coach for the football club of his alma mater University of Tsukuba, and taught for several years at Rikkyo University. In 2001, he coached the Japan U-17 national team, to which he led for the first time since 1995 in the first round of the 2001 U-17 World Championship.