He was born as the eldest of four children of Tantaro and Fuji NAKARAI in Tsushima Fuchu Domain, present-day Izuhara-machi, Tsushima City, Nagasaki Prefecture.
半井湛太郎・藤の4人弟妹の長男として対馬対馬府中藩、現在の長崎県対馬市厳原町に生まれる。