Lifespan: Unknown to 6/4 of Kyōroku 4 (1531)
Name Changes: Iwachiyomaru → Yoji → Saburō-zaemon-no-jō Kunimori
Bakufu: Muromachi – Deputy military governor of Settsu
Lord: Hosokawa Takakuni
Father: Yakushiji Motokazu
Siblings: Kuninaga, Kunimori
Yakushiji Kunimori served as a bushō during the Sengoku period. He was a retainer of the Hosokawa-Keichō family and served as the deputy military governor of Settsu Province.
Kunimori was born as the son of Yakushiji Motokazu. In the era of Motokazu, the role of the deputy military governor of Settsu was divided with Motokazu serving in this role in the upper districts and his younger brother, Yakushiji Nagatada in the lower districts. After a failed rebellion by Motokazu against Hosokawa Masamoto, the roles were recombined under Nagatada. In the sixth month of 1507, Nagatada participated in a plot to assassinate Masamoto known as the Lord Hosokawa Incident and backed Hosokawa Sumiyuki. Following the demise of Sumiyuki in the eighth month, Hosokawa Sumimoto and Hosokawa Takakuni engaged in a prolonged succession struggle known as the Conflict between the Hosokawa.
After Takakuni acquired the headship of the Hosokawa-Keichō family, he engaged the services of Motokazu’s orphans, Mantokumaru (Yoichi, Kurōzaemon Kuninaga) and Iwachiyomaru (Yotsugi, Saburōzaemon Kunimori). Similar to the division of responsibilities between Motokazu and Nagatada, the two siblings divided the role of deputy military governor of Settsu.
As the offensive by Hosokawa Harumoto gained momentum, in 1528, the Yakushiji siblings temporarily surrendered to Harumoto. In the eighth month of 1530, he fought against supporters of Takakuni at Tomatsu Castle in Settsu but was defeated and, in the ninth month, fled to Daimotsu Castle. After Takakuni’s forces assaulted Daimotsu Castle, he was forced to surrender in the eleventh month and thereafter affiliated with Takakuni.
In the fourth month of 1531, Kunimori joined Takakuni to invade Kyōto. At Yamazaki, these forces were defeated by Miyoshi Motonaga, a bushō under their former lord, Hosokawa Harumoto. In the sixth month, Kunimori is deemed to have been killed during the Collapse at Daimotsu.