Yamaguchi

The Yamaguchi of Musashi were a branch of the Murayama party, one of the seven warrior bands of Musashi, and claimed descent from the Kanmu Heishi line of the Taira. The party's founder Taira no Yorito held Murayama, and his grandson Ietsugu settled at Yamaguchi in Iruma district and took its name; generations of the clan were based at Yamaguchi Castle.

In the Musashi Heiikki uprising of 1368 the Yamaguchi sided with the Kawagoe clan, and their castle fell to Uesugi Noriaki, acting for Ashikaga Ujimitsu. In 1383 Takaharu, backed by the Southern Court, rose again with his grandfather Takazane but was defeated; they set fire to Yamaguchi Castle and took their own lives.

Takatada, Takaharu's son, entered Uesugi service and later served the Later Hojo. After the Hojo fell in 1590 his descendants, including Yamaguchi Daizen, served the Tokugawa.