Kuroki Sadao was born in Nobeoka, Miyazaki prefecture. After having studied western-style painting he studied hanga in a short course with Un'ichi Hiratsuka (1895-1997) in Oita in 1934 and with Kôshirô Onchi (1891-1955) after that. He was a member of the Nihon Hanga Kyôkai and of many other print groups.
He contributed to Kitsutsuki hangashû, 1943, and to Picture notes on native customs of Japan - Nihon minzoku zufu in 1946. His signature is often "SA" or the character 貞 on early prints.
