- Born: 1524
- Died: 1575
- Title: Saburô Byoue no Jô
- Distinction: One of Takeda Shingen's 24 Generals
- Japanese: 山県昌景 (Yamagata Masakage)
Named among Takeda Shingen's 'Twenty-Four Generals', Yamagata Masakage was one of the fiercest of the Takeda warriors. Masakage's elder brother Obu Toramasa was charged with treason in 1565 and executed; some believe it was Yamagata who revealed his conspiratorial activities. Yamagata fought in many of Takeda Shingen's battles and was given a fief in Shinano. He was present at the Battle of Mimasetoge in 1569 and captured Yoshida Castle, a Tokugawa possession, during the Mikatagahara Campaign (1572-73) and was present for the following Battle of Mikatagahara. Borrowing from his late brother, Yamagata outfitted as many of his personal retainers as possible in bright-red armor, earning Yamagata's troops the nickname 'Red Regiment', or 'Red (Fire) Unit', though the phrase may have been coined later. At Nagashino (1575) Yamagata commanded the vanguard of the Takeda's left wing and was shot from his horse assaulting the Oda/Tokugawa lines. According to legend, Shingen called out to Yamagata from his deathbed in 1573 and ordered him to plant his banners at the Seta Bridge, the traditional eastern gateway to Kyoto.
- Initial text from Samurai-Archives.com FWSeal & CEWest, 2005