Yoshisaburo "Sabu" Toyozumi (born Tsurumi, Yokohama; 1943) is one of the small group of musical pioneers who comprised the first generation playing free improvisation music in Japan. As an improvising drummer he played and recorded with many of the key figures in Japanese free music including the two principal figures in the first generation, Masayuki Takayanagi and Kaoru Abe from the late 1960s onwards. He is one of a very few of this circle who are still alive and engaged in playing this music today.

Toyozumi features on numerous commercially available recordings with many of the most notable Japanese and international improvising musicians including Derek Bailey, Mototeru Takagi, Misha Mengelberg, Peter Brötzmann, Keiji Haino, Otomo Yoshihide, Tom Cora and Fred Van Hove.

In 1971 he became the only non-American member of the Association for the Advancement of Creative Musicians(AACM)). He dedicated his first record as a leader, Sabu – Message to Chicago, to compositions by AACM members, and in 1992 toured and recorded with AACM trumpeter Wadada Leo Smith.

Toyozumi has been instrumental in bringing many European and American improvisers to Japan including Derek Bailey, Misha Mengelberg and Sunny Murray.

In 2005 British improvising guitarist and promoter John Russell arranged a two-day event dedicated to Toyozumi in which the drummer performed in different groupings with 14 musicians from the London improvised music scene including, most notably, Evan Parker, Lol Coxhill, Phil Minton, John Edwards and Steve Beresford. The Wire described his playing at this time as follows: "He’s busy, but there’s always space between his notes, and he avoids the flashy technical solution to musical problems. His playing is crisp and dramatic, with a very occasional use of repetition to spark a climax. If it’s possible for a drum kit to ask awkward questions, Toyozumi seems to be doing it".

In an interview with Cadence Magazine in 1988 Toyozumi makes clear the importance of his relationship with nature as an influence on his playing and Clive Bell writing in The Wire in 2005 notes "his devotion to the way of Watazumido, the late shakuhachi player and Zen master, whose performances mixed martial arts and music in a bizarre cocktail of discipline and craziness".

In 2009 he returned to London to feature as one of the players in Russell's improvisation festival Fete Quaqua which was recorded for broadcast by BBC Radio 3. He continues to tour widely and in the past year or so has performed in Belgium and France, Chile, Taiwan, England, Philippines and Greece. He also performs from time to time with the legendary Japanese noise group Hijokaidan. Currently he performs on the erhu – a two-stringed Chinese violin – as often as playing the drums.