In 1333, when Emperor Godaigo rose in revolt against the bakufu and urged the Gozoku (local ruling family) of various places to rise to action, Sadahisa SHIMAZU who was the fifth head of the Shimazu soke joined the forces of overthrowing the Shogunate.
正慶2/元弘3年（1333年）、後醍醐天皇が幕府に叛旗を翻し各地の豪族に決起を促すと、島津宗家5代当主、島津貞久は倒幕軍に加わる。