Yoshizawa collaborated with innumerable musicians over his long career; some of the better known include Masayuki Takayanagi, Masahiko Togashi, Takehisa Kosugi, Mototeru Takagi, Kaoru Abe, Steve Lacy, Dave Burrell, Derek Bailey, Evan Parker, Barre Phillips, Butch Morris, Elliott Sharp, Ikue Mori, Keiji Haino, Kan Mikami, Kazuki Tomokawa, Christopher Yohmei Blasdel & Tenko.
Yoshizawa began playing in a free style in the mid-1960s, in groups with Yosuke Yamashita and Kazunori Takeda, as well as in a famous jam session with Elvin Jones during John Coltrane's Japan tour of 1966.
Yoshizawa's own trio with Mototeru Takagi was pivotal for Japanese free jazz,[1] though no recordings survive.
Yoshizawa was a pioneer of solo bass performance, his experiments synchronous with those of Barre Phillips.
Later in the decade he had a fruitful collaboration with alto saxophonist Kaoru Abe, which led to the recording of one album, Nord.