He was born in 1842 as the second son of Hikohachi Tsunamasa OYAMA, a feudal retainer of the Satsuma clan, on the Kakimotoderadori Street in Kajiyacho Town (Shimokajiyacho Hogiri) near Kagoshima-jo Castle in Satsuma Province (His childhood name was Iwajiro.)
天保13年（1842年）、薩摩国鹿児島城下加治屋町柿本寺通（下加治屋町方限）に薩摩藩士・大山彦八綱昌の次男として生まれた（幼名岩次郎）。