Ogasawara clan
Nagamichi was the eldest son of Ogasawara Nagamasa, the first Ogasawara daimyō of Karatsu Domain in Hizen Province, Kyūshū, Japan (modern-day Saga Prefecture). An infant at the time of his father’s death, he was bypassed in the succession by Ogasawara Nagayasu, originally the son of Sakai Tadaari of Shonai Domain. Nagayasu died without heirs, and was replaced in turn by Ogasawara Nagao, and Ogasawara Nagakazu, each of whom was adopted into the Ogasawara clan as a successor, and each of whom died without heirs.