Dairoku's name comes from the fact that he was born in the 6th year of the Taishō period at Itoshima, Fukuoka (roku means "six" in Japanese).
After repatriation, he became an archaeologist, and named himself Hachimusai (one who does not have the eight (hachi) things: land, a house, money, a school career, documents, books, a wife, and a job).
Starting in the spring of 1947, he learned archaeology from Heijiro Nakayama, a noted archaeologist living in Fukuoka; this lasted for nine years.
Through investigations and excavations, Dairoku came to the conviction that the family of Japanese emperors originated in this area.
In early 1950 he first wrote a paper entitled The origin of Japan; studies on the development of kofun culture.