Lifespan: Tenbun 16 (1547) to 8/10 of Tenshō 13 (1585)
Other Names: Gyōbuzaemon (common)
Lord: Satsuma Yoshihiro
Father: Kinowaki Sukesada
Mother: Daughter of Machida Tango-no-kami
Siblings: Sukemasa, Sukeharu (third son)
Children: Sukeyoshi (also known as Sukesada), Sukehide
Kinowaki Sukemasa served as a bushō during the Sengoku and Azuchi-Momoyama periods. He was a retainer of the Shimazu clan of Satsuma Province.
Sukemasa was born as the lineal heir of Kinowaki Sukesada. He served Shimazu Yoshihiro, a daimyō and the seventeenth head of the Shimazu clan.
In 1566, Sukemasa made contributions during an assault on Mitsuyama Castle in Hyūga Province. In the tenth month of 1583, Sukemasa was appointed as the lord of Hana-no-yama Castle and lord of the manor in Higo Province. In the eighth month of 1585, he was surrounded by a contingent of 8,000 soldiers led by Kai Chikahide, a retainer of the Aso clan of Higo. Sukemasa, joined by Kamata Masatora and reinforcements from the Sagara clan fought valiantly to defend the castle. Sukemasa, however, incurred injuries, whereupon he read a death poem and then charged into the enemy forces, dying in battle. While the castle fell, Masatora, Fukami Settsu-no-suke (the son of Fukami Nagatomo, a chief retainer of the Sagara), and over thirty others were killed in action.