Lifespan: Eishō 17 (1520) to Tenshō 1 (1573)
Other Names: Bitchū-no-kami
Lord: Imagawa Yoshimoto → Imagawa Ujizane → Takeda Shingen
Father: Katsurayama Sadauji
Adoptive Father: Katsurayama Ujihiro
Siblings: Tsunaharu (?)
Children: Ofuchi (wife of Katsurayama Nobusada)
Katsurayama Ujimoto served as a bushō during the Sengoku period. He was a kunishū, or provincial landowner, in the Suntō District of Suruga Province and served as the lord of Kazurayama Castle.
The landholdings of the Katsurayama extended over a broad area in the eastern portion of Suruga. This territory was located at the juxtaposition of Suruga (governed by the Imagawa clan), Kai (governed by the Takeda), and Sagami (governed by the Gohōjō) provinces. While the Katsurayama were obedient to the Imagawa, the clan also had deep ties to the Takeda and the Gohōjō which swayed along with the balance of power among these daimyō families.
Ujimoto was adopted by Katsurayama Ujihiro, the lord of Kazurayama Castle and a kokujin subservient to the Imagawa.
Ujimoto originally served the Imagawa, but, in the latter part of the Eiroku era (1558 to 1570), relations between the Takeda and Imagawa clans deteriorated and, at the end of 1568, Takeda Shingen launched the Invasion of Suruga. On this occasion, Ujimoto colluded with the Takeda including Asahina Nobuoki and the Sena clan, but lost Kazurayama Castle to the Gohōjō acting in support of the Imagawa against the Takeda.
On 2/1 of Eiroku 12 (1569), Ujimoto joined with a retainer of the Takeda named Anayama Nobutada to assault Ōmiya Castle defended by Fuji Nobutada of the Fuji District of Suruga who had the support of the Gohōjō of Sagami allied with the Imagawa clan.
In 1571, after the Takeda and Gohōjō reached a settlement that led to a transfer of Kazurayama Castle from the Gohōjō to the Takeda. The castle, however, did not revert to the control of Ujimoto. Instead, in 1572, the castle was assigned to Takeda Nobusada (the sixth son of Takeda Shingen). Nobusada was a district landowner but did not move to Kazurayama Castle, instead, Mishuku Tomotsuna served as the chamberlain of the castle. There are various theories concerning this transition. Under one theory, Shingen executed Ujimoto and transferred the castle to Nobusada. Alternatively, Ujimoto initially adopted Nobusada and transferred headship of the clan and the castle to him. Then, at the end of the second month of 1573, owing to suspicions of plotting a rebellion, Ujimoto was executed at Suwa in Shinano Province. In either case, Nobusada acquired control of the castle and Ujimoto was eliminated.
In the third month of 1582, the Kai-Takeda clan was decimated in battle against the Oda clan. Thereafter, Kazurayama Castle was abandoned.