Shimazu Sadahisa was the fifth head of the Shimazu clan.
The son of Shimazu Tadamune, Sadahisa joined the Ôtomo and Shôni clans in 1333 in siding with Emperor Go-Daigo and Ashikaga Takauji against the Kamakura shogunate. Among his chief contributions to this military effort was invading Dazaifu and attacking Chinzei tandai Hôjô Hidetoki, at the court's request; as a reward, he was granted authority over Ôsumi and Hyûga provinces, restoring Shimazu control over the full range of territory Shimazu Tadahisa held 120 years earlier.
When Takauji rebelled against Emperor Go-Daigo, Sadahisa joined Takauji in this as well, fighting against the Kimotsuki, Nejime, Taniyama, and Ijûin clans. In 1341, Sadahisa took the Southern Court fortress of Tôfukuji castle (located within his territory, in Kagoshima city), and named his son Shimazu Ujihisa castellan.
Sadahisa then defected to the side of the Southern Court in order to attack Go-Daigo's son, Prince Kaneyoshi, but returned again to the side of the Northern Court shortly afterwards. When, in the Kannô era (1350-1352), Sadahisa sided with Takauji against the latter's son, Ashikaga Tadayoshi.
He died in 1363, at the age of 95. Since his eldest son Shimazu Yorihisa, and second son, Shimazu Munehisa, died young, the succession was divided between his other sons, Shimazu Morohisa and Shimazu Ujihisa. Sadahisa had lost control of Hyûga province sometime earlier; Ujihisa was named shugo of Satsuma, and Morohisa shugo of Ôsumi, marking the division of the Shimazu clan into Sôshû and Ôshû branches, respectively.
|Head of Shimazu clan & jitô-shugo of Satsuma province
Shimazu Ujihisa & Shimazu Morohisa