Lifespan: 15xx to 16xx
Other Names: Seto Tanemoto, Jūrōbei (common)
Title: Governor of Izu
Clan: Amakusa, Seto
Lord: Amakusa Naotane → Amakusa Shigehisa → Amakusa Hisatane → Konishi Yukinaga
Father: Amakusa Hisatake
Siblings: Tanemoto, sister (wife of Amakusa Shigenao)
Wife: Daughter of Amakusa Naotane
Amakusa Tanemoto served as a bushō during the Sengoku and Azuchi-Momoyama periods. A Christian convert, Tanemoto served as the lord of Hondo Castle in Higo Province in Kyūshū.
Tanemoto originated from a cadet family of the Amakusa clan who were one of the Five Clans of Amakusa, kokujin, or provincial landowners, in the Amakusa archipelago of Higo. For a while, Tanemoto also used the Seto surname.
Tanemoto was born as the son of Amakusa Hisatake and was a brother-in-law of Amakusa Shigenao (the son of Amakusa Naotane), however, there are different theories as to whether Naotane was Tanemoto’s father or Shigenao had another name of Hisatake and Tanemoto was adopted.
At Amakusa, in 1569 during the era of Shigenao, he invited a Portuguese missionary named Luís de Almeida and engaged in evangelical activities, increasing the number of Christian converts. In 1570, Tanemoto and his father, Hisatake, were baptized. His baptismal name was Johan. Under another theory, it was Andrea.
In 1582, Tanemoto inherited the headship of the clan. A military tactician named Marume Nagayoshi practiced the arts under Tanemoto at Hondo Castle for two years. In 1587, during the Kyūshū Pacification by Toyotomi Hideyoshi, Tanemoto submitted to Hideyoshi and received recognition of his rights to his territory.
In 1589, after Shiki Shigetsune and Shiki Morotsune (father and son) rebelled against demands to assist in the construction of Uto Castle for Konishi Yukinaga, Tanemoto, along with Amakusa Hisatane, Ōyano Tanemoto, Kōtsuura Tanenao, and Sumoto Chikataka from the Five Clans of Amakusa acted in concert with them, triggering the Tenshō Battle of Amakusa. Tanemoto, however, lost Hondo Castle and surrendered in the face of an assault by Yukinaga and allied forces under the command of Katō Kiyomasa. Under another theory, he may have died at this time.
Thereafter, he became a yoriki, or security officer, for Konishi Yukinaga and deployed for the Bunroku-Keichō Campaign on the Korean Peninsula. In 1600, he participated in the Battle of Sekigahara and, after the war, was turned over to the custody of Kobayakawa Hideaki in Okayama in Bizen Province.