Lifespan: Eiroku 12 (1569) to 4/17 of Tenshō 15 (1587)
Lord: Shimazu Yoshihisa
Father: Shimazu Yoshitora
Mother: Ohira (eldest daughter of Shimazu Yoshihisa)
Adoptive Father: Shimazu Toshihisa
Siblings: Sister (wife of Shiki Chikahiro), Tadatoki, Tadachika, Tadakiyo, Tadanaga, Irikiin Shigetaka, Tadatoyo, sister (wife of Ogawa Arisue) (?)
Wife: Daughter of Shimazu Toshihisa (Yuno-o)
Shimazu Tadachika served as a bushō during the Azuchi-Momoyama period. He was a retainer of the Shimazu clan.
In 1584, Tadachika was born as the second son of Shimazu Yoshitora. Tadachika was adopted as a designated heir by his great uncle, Shimazu Toshihisa (the younger brother of Shimazu Yoshihisa), who did not have a son and wed Toshihisa’s eldest daughter.
In 1586, Tadachika was assigned as a vice general to subdue a rebellion by Tsukushi Hirokado. Owing to his youth, and the fact this was his first experience in battle, Yoshihisa had Tōya Shinano-no-kami Yoshitoki and Kinowaki Sukesada accompany him and, on 7/6, they attacked Takatori Castle. On 7/26, Tadachika participated in the Siege of Iwaya Castle. He made contributions attacking from one of the entrances.
In 1587, at the Pacification of Kyūshū ordered by Toyotomi Hideyoshi, the Shimazu clan were on the defensive, while the strategically important location of Nejirozaka in Hyūga Province was occupied by Miyabe Keijun. Tadachika proposed launching a nighttime attack to recover Nejirozaka, but was opposed by Shimazu Iehisa (the younger brother of Yoshihisa and Toshihisa) who regarded the plan as reckless. He overcame these objections and attacked Nejirozaka. The opposing forces, however, had anticipated the attack by the Shimazu and, owing to their counterattack, the forces led by Tadachika were almost completely annihilated in a clash known as the Battle of Nejirozaka.
Tadachika himself incurred injuries from arquebus fire, causing severe bleeding. After requesting water from a retainer named Kamata Masakane, Masakane plucked an unripe plum from a nearby tree and offered that to him in lieu of water. Tadachika took one bite and then died. He was nineteen years old. His retainers placed his body on a shield to return.
His eldest son, Shimazu Tsunehisa, who was born in the first month of that year, was raised by Toshihisa and the genealogy of the Hioki-Shimazu family continued.