Oshima was a Himegimi (daughter of a person of high rank) of the Oyumi Kubo family which was a branch family of Koga kubo family, Kanto Kanrei (A shogunal deputy for the Kanto region) and came from the most distinguished ancestry among Hideyoshi's concubines.
お嶋は、関東管領・古河公方家の分家である小弓公方の血を継ぐ名門の姫君であり、秀吉の側室達の中では、もっとも高い家柄の出となる。