- Other names: Igawa Sôgen, Shinjirô
- Title: Wakasa no kami
- Distinction: Hatakeyama retainer
Mitsunobu served the Hatakeyama of Noto province. When the chief Hatakeyama retainers forced Hatakeyama Yoshitsugu to retire in favor of his son, Yoshitsuna (1551), Mitsunobu emerged as an ally of Yoshitsugu and Yoshitsuna. The retainers established a council of seven members to rule the province behind Yoshitsuna; when one of the seven died, the Hatakeyama contrived to have Mitsunobu named as his replacement. He was a capable administrator and a loyal retainer, helping the Hatakeyama to restore their authority in 1555, although his ultimate fate is unknown.
- Initial text from Samurai-Archives.com FWSeal & CEWest, 2005