Lifespan: Unknown to 5/16 of Eiroku 12 (1569)
Title: Senior Assistant Minister of Popular Affairs
Clan: Ogiyama-Amano clan (descended from the Tō family)
Lord: Amano Takatsuna → Mōri Motonari
Father: Amano Okisada
Mother: Daughter of Amano Motosada
Siblings: Takatsuna, Motosada, Chōgetsu
Wife: Daughter of Asonuma Hirohide
Children: Daughter (formal wife of Amano Motomasa)
Adopted Children: Amano Motomasa (seventh son of Mōri Motonari)
Amano Motosada served as a bushō during the Sengoku period. He was a retainer of the Mōri clan and head of the Fukino-Amano clan, a kokujin, or provincial landowner, based at Yoneyama Castle in the Shiho manor in the Kamo District of Aki Province. Motosada adopted Chitoramaru (the seventh son of Mōri Motonari) whose name was changed to Amano Motomasa.
Motosada was born the son of Amano Okisada, the head of the Fukino-Amano clan and a retainer of the Ōuchi and Amago clans.
In 1541, Okisada was succeeded by his eldest son, Amano Takatsuna. However, Takatsuna died shortly after the Battle of Itsukushima on 11/27 of 1555. Takatsuna did not have an heir, so, upon the recommendation of Mōri Motonari, in the tenth month of 1556, Motosada became the next head of the family.
Motosada participated in the Subjugation of Bōchō (Bōchō keiryaku) and, on 3/14 of 1556, attacked an uprising by locals in Katsurano in the Kuga District of Suō Province, killing several and suppressing the uprising. On 4/19 of 1556, in battle against the Sue army on Mount Myōken in Kudamatsu in the Tsuno District of Suō, Motosada fought valiantly along with Kumagai Takatsune and others, killing over 500 enemy forces in an major victory.
Beginning in the seventh month of 1562, Motosada joined in the Izumo Expedition led by Motonari. In 1565, in battle at the Mikomori entrance of the Gassantoda Castle, Motosada and Amano Takashige daringly violated the military rules by rushing to the front to fight in support of Mōri Terumoto as his army pushed forward.
Motosada died on 5/16 of 1569. Motosada did not have an heir either, so according to his will, on 6/23 of the same year, Motomasa (the seventh son of Motonari), in his capacity as the adopted son-in-law, succeeded him as the head of the Amano clan. Moreover, on 5/22, Katsura Mototada sent a letter concerning the succession plans for the Amano clan to fourteen elders of the clan.