Isoo Fukui, born October 10, 1945, in Fukuoka Prefecture, is best known for a single, essential session: on March 1, 1974, he played bass on Midnight Sugar at Aoi Studio in Tokyo, the debut album of pianist Tsuyoshi Yamamoto, with drummer Tetsujiro Obara completing the trio. The album won the Swing Journal Jazz Disc Award and Best Engineering Award that year and established Yamamoto as one of the two defining artists on Three Blind Mice, the label most responsible for the international Japanese-jazz reissue wave. It has since been reissued by Light in the Attic and remains, half a century on, one of the records most cited as an entry point to the genre.

Fukui is described in secondary coverage as one of a small handful of 1970s players who genuinely reshaped how the bass functioned in Japanese jazz — playing both double bass and cello with a sound built around soul, rhythm, and a modal sensibility rather than conventional walking lines. He played on the Yamamoto Trio's second album, Misty, the same year, and spent much of the decade as a fixture of the Masaru Imada Trio, including Poppy (1973, also on Three Blind Mice), Green Caterpillar (1975), and One for Duke (1975). He also recorded extensively with the Hideo Ichikawa Trio through the mid-to-late 1970s.

He led his own dates under several billings across the same period — the Isoo Fukui Quartet (Sunrise/Sunset, 1976), Isoo Fukui And His Friends (Duo, 1977), and Isoo Fukui & Flyin' ('Round About Midnight, 1981) — but his own name almost never carried an album beyond these. His discography as a headline artist stayed thin throughout his career; his significance rests overwhelmingly on the sessions he shaped rather than the ones he led.

Fukui's playing is characterized in secondary sources as unusually soulful and rhythmically forward for its era, with a modal sensibility that set his contribution to Midnight Sugar and the Masaru Imada Trio records apart from more conventional straight-ahead walking-bass approaches common in Japanese piano-trio jazz of the period.