Lifespan: Bunmei 9 (1477) to 9/20 of Eishō 1 (1504)
Other Names: Yoichi, Kurōzaemon
Title: Governor of Bingo
Bakufu: Muromachi – Deputy military governor of Settsu
Lord: Hosokawa Masamoto
Father: Yakushiji Motonaga (or Yakushiji Nagamori)
Siblings: Motokazu, Nagatada, Teramachi Matasaburō, Akutagawa Nobukata
Wife: [Formal] Daughter of the Settsu-Arima clan (members of the Akamatsu clan)
Children: Kuninaga, Kunimori
Yakushiji Motokazu served as a bushō during the Sengoku period. He was a senior retainer of the Hosokawa-Keichō family and served as the deputy military governor of Settsu Province.
Motokazu was regarded as the natural son of Yakushiji Motonaga, but the current prevailing view is that he was eldest son of Yakushiji Nagamori (Motonaga’s younger brother) and later adopted by Motonaga who had no children of his own. He received one of the characters in his name from Hosokawa Masamoto and adopted the name of Motokazu.
In 1500, upon orders of Masamoto, he assisted Hatakeyama Yoshihide of Kawachi Province and contributed to the defeat of Hatakeyama Hisanobu.
In 1501, after the death of Motonaga, Motokazu inherited the headship of the clan and became the deputy military governor of Settsu, serving Masamoto. Based on another theory, 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 succeeding his natural father, Nagamori. After the failed rebellion by Motokazu, the roles were recombined under Nagatada.
In 1503, upon orders of Masamoto, Motokazu facilitated negotiations for the adoption of Hosokawa Sumimoto from the branch of the Hosokawa family in Awa Province.
In the third month of 1504, Masamoto suddenly sought to remove Motokazu from his position as the deputy military governor. Ashikaga Yoshizumi, the eleventh shōgun of the Muromachi bakufu, intervened and ordered Masamoto to suspend the removal of Motokazu from his position. Thereafter, Motokazu offered a horse and long sword as gifts to Yoshizumi.
On 9/4 of Eishō 1 (1504), Motokazu, together with Akazawa Tomotsune, conspired to remove Masamoto and back Sumimoto as his successor. He then joined his second youngest brother, Teramachi Masasaburō (adopted by Teramachi Michitaka) and raised arms in Settsu. He was then attacked by his first youngest brother, Nagatada, and defeated. On 9/19, his base at Yodo Castle fell and he was apprehended. That same day, upon orders of Masamoto, he was sent to Kyōto and, on 9/20, was compelled to take his own life. Motokazu was twenty-eight years old. Thereafter, Nagatada inherited the headship of the clan and the role of deputy military governor of Settsu.
Motokazu’s youngest brother, Akutagawa Nobukata (adopted by Akutagawa Bingo-no-kami) did not participate in the rebellion but was known as a member of Sumimoto’s faction and, as a result, murdered by Takakuni in Sakai in the fifth month of 1508.
Motokazu’s orphans, Mantokumaru (Yakushiji Kuninaga) and Iwachiyomaru (Yakushiji Kunimori) were rescued and engaged in service by Takakuni. This appeared to be out of consideration for the relationship between the Hosokawa and Akamatsu clans given that Motokazu’s formal wife originated from the Settsu-Arima clan who were members of the Akamatsu clan.