Lifespan: 15xx to 15xx
Rank: bushō, shugo daimyō, sengoku daimyō
Title: Governor of Harima
Bakufu: Muromachi – Military Governor of Kii, Kawachi, and Etchū provinces
Father: Hatakeyama Hisanobu
Siblings: Tanenaga, Nagatsune, Masakuni, Haruhiro, Harukuni, Hosokawa Harunobu
Children: Takamasa, Masahisa, Akitaka
Hatakeyama Masakuni served as a bushō, shugo daimyō, and sengoku daimyō of Kii, Kawachi, and Etchū provinces. Masakuni originated from the Hatakeyama-Bishū family.
The Hatakeyama clan was one of the three deputy shōgun families of the Muromachi bakufu. Masakuni was of the lineage of the eldest son. However, with respect to the bakufu administration, his grandfather, Hatakeyama Masanaga, took his own life after being cornered by Hosokawa Masamoto. This prevented Masakuni from participating in the bakufu and, in a dispute over the choice of a successor, the family split into the Sōshū and Bishū branches. While this may have been advantageous for the Bishū family, the rupture was not resolved even in the era of Masakuni. In the Sengoku period, when those of lower rank usurped their masters in a phenomenon known as gekokujō, military governors often confronted with power-struggles involving their senior retainers.
In 1545, after the death of his older brother, Tanenaga, a senior retainer named Yusa Naganori was backed to become the next head of the clan, but his older brother had acted in concert with Hosokawa Ujitsuna who launched a rebellion against Hosokawa Harumoto – a powerful figure in the Muromachi bakufu, so he did not receive recognition from the bakufu to become the next head of the clan and, instead, an individual named Hatakeyama Shirō received support (although he did not receive the support of retainers and was soon expelled). To halt interference by the bakufu, the band of retainers including Naganori backed Masakuni and continued supporting Ujitsuna. Masakuni was recognized not as the head of the clan, but as a proxy for the head of the clan.
In 1549, at the Battle of Eguchi, Naganori, together with Miyoshi Nagayoshi, defeated the faction supporting Harumoto. After Harumoto and Ashikaga Yoshiteru (the thirteenth shōgun of the Muromachi bakufu) fled from the Kinai, Masakuni came into conflict with Naganori in regard to their policies, whereupon Masakuni entered the priesthood to live a secluded life in Kii Province. Following his retirement, Masakuni’s eldest son, Hatakeyama Takamasa, became the head of the clan.
Masakuni is said to have died in 1550, but, there is a record indicating that he was retired and in good health as of the second month of 1552 so it appears he died after that time. Given that his sibling named Hatakeyama Haruhiro adopted the name of Harima-no-kami and an individual named Hatakeyama Yakurō was formerly regarded as the same person as Masakuni, the career of Haruhiro from 1536 to 1538 and those of Yakurō from 1538 to 1541 are confused with the career of Masakuni.