Tadamune was the son of Ijuin Tadaao and an important Shimazu retainer who served in many of Shimazu Yoshihisa's campaigns and battles, including Mimigawa (1578). During Toyotomi Hideyoshi's invasion of Kyushu in 1587, Tadamune ended up assisting in negotiations between Hideyoshi and the Shimazu. He impressed Hideyoshi and found himself treated as almost an equal to the Shimazu. Tadamune in fact began to act as if he were an independent lord and was haphazard in his duties to the Shimazu. In 1595 he was transferred from Koyama to an 80,000-koku fief at Miyako-no-sho on Hideyoshi's orders and led over 2,000 men in the 2nd Korean Campaign (1597-98). However, he was summoned on 4/4/1599 to Shimazu Tadatsune's mansion and was there murdered.
References
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005