Shimazu Ujihisa was the head of the Ôshû branch of the Shimazu clan, and shugo of Ôsumi province, at a time when the clan was split into his Ôshû branch, and his brother Shimazu Morohisa's Sôshû branch. Both share the distinction of being the 6th head of the Shimazu clan, and the clan, split by their succession, was reunited after their death with Ujihisa's descendants continuing as the main trunk lineage.
The fourth son of Shimazu Sadahisa, he made Tôfukuji castle in Kagoshima his seat in 1341. Though he later relocated to Ôaira and Shibushi castles, this represents the beginning of Kagoshima as the Shimazu seat; the city would remain the clan seat for the next five hundred years.
Ujihisa fought on the side of the Ashikaga clan and the Northern Court in the Nanboku-chô conflict, as well as standing opposed to Kyushu tandai Imagawa Ryôshun. He became shugo of Ôsumi province in 1363, just as his elder brother Morohisa became lord of Satsuma province, and head of the Sôshû branch of the family. When Ashikaga Takauji turned against his brother Ashikaga Tadayoshi, Ujihisa remained loyal to Takauji, and briefly joined with Southern Court forces to fight Tadayoshi. In 1375, while attacking Mizushima in Higo province, Ujihisa's ally Shôni Fuyusuke was betrayed and killed by Imagawa Ryôshun; furious, Ujihisa and his nephew Shimazu Korehisa joined the Southern Court side in order to oppose Imagawa. As a result, the following year, the Ashikaga shogunate stripped Ujihisa of his official appointment as shugo of Ôsumi.
|Head of Ôshû Shimazu clan
& lord of Ôsumi province