Sai is a director and screenwriter who first started to work in the film industry as a lighting technician’s assistant. He made his debut with the film
Tsuki wa dotchi ni deteiru (All under the moon, 1993), and also made
Jukkaino mosquito (1983),
Itsuka darekaga korosareru (1984),
A Sign Days (1989),
Mâkusu no yama (Marks, 1995),
Buta no mukui (1999),
Keimusho no naka (Doing Time, 2002),
Quill (2004) and
Chi to hone (Blood and Bones, 2004).