Fukui started out in Yokohama during a time when Japanese musicians were figuring out how to play jazz in their own way, not just copying what Americans were doing. In the late 1960s you can hear him listening closely to McCoy Tyner's dense piano playing and Herbie Hancock's electric work, but he took those ideas and made them quieter and more personal.
His best-known work came out in 1976 with Scenery. Six songs that manage to feel both small and big at once, played with bassist Yoshihito Yoshimura and drummer Tsuguhito Nakaoka. "Early Summer" is calm and spacious; the title track lets silence do a lot of the work. The thing that makes it special is that he never separated what jazz musicians do from what he wanted to say — it just fit together naturally.
He kept experimenting afterward. Mellow Dream (1971, recorded before Scenery but released later) shows him moving into fusion and electronic textures without losing the warmth that made his playing feel human.
For a long time, most people in the West had no idea who he was — not because he wasn't good, but because he recorded for small Japanese labels that never shipped overseas. Now that his records are on streaming and getting repressed on vinyl, people are finally hearing what he accomplished. Full catalog on his artist page.