[1] Watanabe was attracted to jazz from an early age, in part due to the strong cultural influence stemming from the American post-war presence in Japan.

[2] He learned the clarinet while in high school after convincing his father over the course of six weeks to buy him a second-hand instrument.

[4] Studying led Watanabe to a broadened stylistic scope that began to incorporate Brazilian music.

[5] In 1969, Watanabe began working part time as a radio broadcaster, promoting jazz across Japan.

In 1970, he released his album Round Trip, featuring Chick Corea, Jack DeJohnette, and Miroslav Vitouš.