Ichimura started in aikido in 1957, at Aikikai Hombu dojo in Tokyo with Shoji Nishio as his main teacher.
In 1966 he moved to Stockholm, since Jan Beime and a few other people had asked Hombu to send an aikido teacher there.
In 1968 he moved to Uppsala, roughly 70 kilometres north of Stockholm, where he started a new dojo in cooperation with the local YMCA.
In 1986, Ichimura returned to Japan, leaving Sweden without a Japanese teacher in charge while Yasuo Kobayashi took responsibility for Finland, and Nishio for Denmark.
However, in connection with the 50 years jubilee in 2011 for aikido in Sweden, Ichimura made a temporary comeback.