Lifespan: 8/17 of Keichō 17 (1612) to 3/26 of Jōou 3 (1654)
Other Names: Tsurukesa (childhood)
Title: Governor of Musashi, Master of Imperial Guards of the Left Division
Lord: Shimazu clan
Father: Tanegashima Hisatoki
Tanegashima Tadatoki served as a retainer of the Kagoshima domain in the early Edo period. He was the seventeenth head of the Tanegashima clan.
In 1612, Tadatoki was born to a consort of Tanegashima Hisatoki, a retainer of the Shimazu clan and the sixteenth head of the Tanegashima clan. Prior to the birth of Tadatoki, in 1611, Hisatoki died without a successor.
Tadatoki was appointed the successor on the premise of having been born to Shimazu Iehisa, the lord of the domain. Given that he was an infant, Tanegashima was administered by the Kagoshima domain while Tadatoki was raised below Kagoshima Castle. In 1620, after his coming-of-age ceremony, Tadatoki received the daughter of Iehisa as his wife. This resulted in the loss of his independence as the ruler of the island.
Thereafter, as a retainer of the Kagoshima domain, Tadatoki traveled between Kagoshima and Edo, serving an important role as a messenger to Tokugawa Hidetada (the second shōgun of the Edo bakufu) and Tokugawa Iemitsu (the third shōgun). Meanwhile, owing to its location, Tanegashima became a key location for holding prisoners of the Kagoshima domain. Tadatoki was responsible for supervising those banished to the penal colony including Katano Katarina (a clandestine Christian and grandmother of Shimazu Mitsuhisa) and Shimazu Hisanori (the adopted son of Shimazu Hisayoshi (a prior chief retainer of the lineage of Shimazu Toshihisa)).
For these reasons, Tanegashima became a site for the exile of criminals of the Imperial Court.
In 1654, Tadatoki died at the age of forty-one.