Oyama Ujimasa

Oyama Ujimasa (1329–1355) was a warrior of the Northern and Southern Courts period and shugo of Shimotsuke Province. His father Hidetomo was killed in the Nakasendai Rebellion of 1335, and the headship passed to his elder brother Tomosato; when Tomosato died without an heir in 1346, Ujimasa inherited the family domains and shugo post.

He joined Ashikaga Takauji against Ashikaga Tadayoshi, fighting at Sattamine Pass in 1351 and Fuefuki Pass in 1352, then campaigned around Kyoto until his death in 1355, aged twenty-seven.