Watanabe was born in Japan in 1938, and commenced training in Shorinjiryu Kenkokan Karate in 1955 under the tutelage of that systems founder, Kōri Hisataka.
[1] In 1967, he was selected by his teacher to move to North America to help spread Shorinjiryu Kenkokan Karatedo.
After demonstrating at World Expo 67 in Montreal, Quebec, Canada (along with Masayuki Hisataka, the founder's son), he settled in Baltimore, Maryland, U.S.A. and opened the Japan Karate Center.
Shunji Watanabe, along with Minoru Morita in the U.S.A. and Shigeru Ishino in Canada, founded the Shorinjiryu Kenyukai Karate Federation.
As of 2012, there are branch dojo on Long Island, NY, USA, and Brisbane, Australia.