Tomonaga Oyama

Tomonaga Oyama was a Kamakura-period warrior, shugo of Shimotsuke and castellan of Oyama Castle, the legitimate heir of Tomomasa. Originally named Masayoshi, he first appears in 1193 as a yabusame archer at Tsurugaoka.

In the Jōkyū War of 1221 he served as a general of the Tōsandō army, helping defeat court forces at the Ōido crossing before entering Kyōto, and afterwards beheaded Hamuro Muneyuki in Suruga by shogunal order. He succeeded to the family headship and died in 1229 aged 42, before his father.