Lifespan: 15xx to 15xx
Title: Governor of Wakasa, Assistant Director of the Bureau of Palace Dining, Assistant Director of the Bureau of Accounting
Lord: Hatakeyama Yoshitsuna
Igawa Mitsunobu served as a bushō during the Sengoku and Azuchi-Momoyama periods. He was a retainer of the Noto-Hatakeyama clan and member of the family of Hanonsai Muneharu, a priest for Hatakeyama Yoshifusa and Hatakeyama Yoshitsugu. Mitsunobu had the common name of Shinjirō.
In 1553, Mitsunobu joined the group of elders in the Second Hatakeyama Group of Seven. This was a political organization of senior retainers who managed the Noto-Hatakeyama clan from 1553 to 1555, following the First Hatakeyama Group of Seven who managed affairs from 1552 to 1553.
Hatakeyama Yoshitsuna served as a sengoku daimyō and the ninth head of the Noto-Hatakeyama succeeding his father, Hatakeyama Yoshitsugu (a sengoku daimyō and the eighth head of the Noto-Hatakeyama). Together with a close associate named Igawa Yoshimune, Yoshitsuna plotted and assassinated Nukui Fusasada (the head of the First Hatakeyama Group of Seven) to reclaim authority by removing Fusasada from his role as the real holder of power in the clan. In an event known as the Kōji Rebellion, the Nukui clan, together with the Miyake clan and adherents of the Ikkō sect in Kaga, joined forces to launch a rebellion against Yoshitsuna. The Nukui backed Hatakeyama Harutoshi, a member of the Hatakeyama family, to become the next head of the clan. During the course of this rebellion, Mitsunobu served as an intermediary between Yoshitsuna and the powerful local clans opposed to him.
While the rebels initially imposed losses on Yoshitsuna’s forces, after a five-year struggle, by early 1560, the Nukui opposition faction was swept from Noto while Yoshitsuna achieved nearly complete victory and the rebellion came to an end. Survivors including Nukui Takakage, Miyake Keipo, and Miyake Tsunahisa appeared to have surrendered. To consolidate power, Yoshitsuna limited the authority of senior retainers who had formerly served in the Hatakeyama Group of Seven, implementing autocratic rule. Mitsunobu served as a close associate of Yoshitsuna during this period. In 1566, Yoshitsuna was ousted from Noto in an event known as the Political Incident of Eiroku 9. At this time, Mitsunobu fled with Yoshitsuna to Sakamoto in Ōmi Province for protection under the Rokkaku clan with whom the Noto-Hatakeyama had a relationship through marriage. Mitsunobu became a central figure in his organization.
In 1573, Mitsunobu entered the priesthood and adopted the name of Wakasa Nyūdō Sōgen.