Oki was born to a Japanese mother and an Ainu father. After graduating in crafts at the Tokyo University of Fine Arts, he moved to New York in 1987, where he worked as special effects artist on film productions.
Oki returned to Japan in 1992, he received his first Tonkori — a traditional stringed instrument developed by the native Ainu people of Sakhalin. Although the instrument was regularly displayed behind glass in museums, there were virtually no traditional players. Oki devoted himself to studying Tonkori and soon began making his own. In 1996 he released his first album ‘Kamuy kor nupurpe.’ Shortly after he established Chikar Studio to in order to encourage other Ainu artists and promote the music of Ainu artists to the world.