Revolt of Honjō Shigenaga
The Revolt of Honjō Shigenaga occurred from the fourth month of Eiroku 11 (1568) to the third month of Eiroku 12 (1569) during which Honjō Shigenaga engaged in battles against Uesugi Kenshin in the environs of Honjō Castle in Echigo Province. At the time, Kenshin was known as Uesugi Terutora.
Outbreak of hostilities
In 1561, at a military council during the Fourth Battle of Kawanakajima, a major conflict fought between Uesugi Kenshin (then known as Uesugi Masatora) of Echigo and Takeda Shingen of Kai, a retainer of the Uesugi named Nagao Fujikage criticized Kenshin’s battle strategy. This led to conflict between Kenshin and Fujikage. Years later, in 1568, upon orders of Kenshin, Honjō Shigenaga, the lord of Honjō Castle in Echigo, invited Nagao Fujikage and Kageharu (siblings) under the pretext of a celebratory banquet and, instead, had them murdered. Although Shigenaga himself incurred an injury in the incident, the objective was accomplished, but Kenshin did not offer any reward for the act.
Dissatisfied with the outcome, Shigenaga responded to a solicitation from Takeda Shingen to block an effort by Kenshin to march to the capital of Kyōto and then planned a revolt. In Noto Province, the Hatakeyama Group of Seven ousted Hatakeyama Yoshitsugu and Hatakeyama Yoshitsuna (father and son). In bid to assist them, Kenshin marched into neighboring Etchū Province to attack Moriyama Castle held by Jinbō Ujiharu who was aligned with the Group of Seven. Shigenaga took advantage of this opportunity to call upon groups of kokujin, or provincial landowners, who had grievances with Kenshin, sending secret letters to each of them. Those receiving the letters included Ayukawa Morinaga and his family, Irobe Katsunaga, Kurokawa Saneuji, and Nakajō Kagesuke (lord of Tossaka Castle) all from the Agakita Group. The Agakita Group was comprised of fiercely independent families located in the northern portion of Echigo.
Kagesuke shared the secret letter with Kenshin, exposing Shigenaga’s planned revolt. Kenshin quickly disbanded his camp, returned to Kasugayama Castle, and proceeded with plans for an attack against Shigenaga’s base at Honjō Castle. Kenshin soon took action. After Ayukawa Morinaga, a member of the Honjō family, pledged his loyalty, then the members of the Agakita Group including the Nakajō, the Irobe, and the Kurokawa followed suit in siding with the Uesugi. Consequently, Shigenaga was forced to hole-up in his castle until reinforcements could arrive from the Takeda army.
Encirclement of Honjō Castle
Although, in the seventh month of 1568, Shingen attacked the Izumi clan (allied with the Uesugi) at Iiyama Castle in Shinano Province, the army could not proceed further. At the same time, Shingen was focused on attacks on Suruga in another direction, so the Takeda did not conduct an active offensive. Shigenaga was supported by Daihōji Yoshimasu from the Shōnai area of Dewa Province. Prior to the attack on Honjō Castle, Kenshin directed forces toward the Daihōji, causing Yoshimasu to quickly surrender and tendered his son, Daihōji Yoshiuji as a hostage. Once Kenshin had at once eliminated the forces supporting the Honjō, from the middle of the eleventh month, he proceeded to encircle Honjō Castle.
Fierce battles and peace negotiations
Despite being surrounded by Kenshin’s forces, Shigenaga held on and, on 1/10 of Eiroku 12 (1569), launched a nighttime raid against the opposing forces that resulted in the killing of Irobe Katsunaga. Nevertheless, by this time, the castle defenses had reached their limit, so, from the middle of the first month, Shigenaga began to explore peace negotiations through the Date and Ashina clans. From the latter part of the second month to the beginning of the third month, a peace accord was reached on the conditions that Shigenaga tender his eldest son, Chiyomaru (later known as Akinaga), as a hostage to Kenshin and that Shigenaga be temporarily confined to his castle. This brought the revolt to an end. Although Shigenaga had revolted and surrendered, his power and influence continued to hold sway in the Uesugi family even after the incident.