 Inō was born in the small village of Ozeki in the middle of Kujūkuri beach, in Kazusa Province (in what is now Chiba Prefecture).He was born to the Jimbo family and his childhood name was Sanjirou.His mother died when he was seven and after a somewhat tumultuous childhood (not uncommon at the time), he was adopted (age 17) by the prosperous Inō family of Sawara (now a district of Katori, Chiba), a town in Shimōsa Province.