Ōkōchi Masatada was born in 1844 as the fifth son of Manabe Akikatsu, lord of the Sabae Domain.

On January 29th, he retreated from his headquarters at Yodo Station.

[1] During the war, Ōkōchi reportedly ate meat from the faces of slain soldiers as an accompaniment to sake.

[2] Although Ōkōchi and Takenaka Shigekata were described by the Imperial authorities as the "ringleaders" (巨魁) of Toba-Fushimi, Ōkōchi was able to protect the Ōtaki Domain from retaliation by the new government by quickly surrendering Ōtaki Castle.

He was survived by his eldest son Ōkōchi Masatoshi, later associated with the Japanese nuclear weapons program in conjunction with General Yasuda Takeo.