 Saotomo was born in Harbin, Manchuria in Northeast China, and thus was raised in Manchukuo; however, following the defeat of Japan in World War II, he was evacuated to Kyushu in 1946.He moved to Tokyo in 1948, and attended Keio University's Literature Department, but left school before graduating.In 1954, the noted author, Yamamoto Shugoro, agreed to become his tutor.