Lifespan: Tenbun 5 (1536) to 9/20 of Tenshō 19 (1591)
Title: Sakon shōgen (Inspector of the Left Division)
Clan: Kunohe branch of the Nanbu clan descended from the Seiwa-Genji
Lord: Nanbu Harumasa → Nanbu Harutsugu
Father: Kunohe Nobunaka
Mother: Daughter of Hachinohe Nobunaga
Siblings: Masazane, Sanechika, Masanori, Nakano Yasuzane, sister (wife of Shichinohe Iekuni)
Wife: [Formal] Daughter of Shinohe Masatsune
Children: Ichizaemon, Danjō, Kamechiyo (Horino Masanobu)
Kunohe Masazane served as a bushō from the Sengoku to Azuchi-Momoyama periods. He was a retainer of the Nanbu clan, serving as the lord of Kunohe Castle.
Origins of the Kunohe clan
The Kunohe were an illegitimate branch of the Nanbu clan of Mutsu Province. In Kenkyū 2 (1191), the founder of the Nanbu clan named Nanbu Mitsuyuki entered the Nukanobu District in Mutsu as the lord of the manor. From this time, his sixth son, Nanbu Yukitsura, settled in Ibonai in the Kunohe District and understood to have adopted the surname of Kunohe. According to other sources, he adopted the surname of Ogasawara, so it is not certain.
From the Muromachi period, the Kunohe appeared to be of the same rank of bushō family as the main branch of the Nanbu clan. Masazane was in the eleventh generation from the era of Yukitsura. Owing to his superior capabilities as a bushō, in the era of Masazane, the Kunohe experience a rise in power but were later extinguished after his rebellion ended in defeat.
In 1536, Masazane was born as the eldest son of Kunohe Nobunaka.
In 1569, upon request of Nanbu Harumasa, Masazane helped to recapture the Kazuno District following an invasion by Andō Chikasue, further expanding his power. When the Shiba clan invaded, Masazane supported Ishikawa Takanobu and enabled a settlement.
Confrontation with Nobunao
Harumasa, the twenty-fourth head of the Nanbu clan, did not have a natural son. In 1565, Ishikawa Takanobu’s son named Nobunao (a younger cousin of Harumasa) wed Harumasa’s eldest daughter and became the adopted son-in-law and designated heir of Harumasa based at Sannohe Castle. Thereafter, Harumasa had his second daughter wed Kunohe Sanechika, the younger brother of Kunohe Masazane, a powerful figure within the Nanbu family. In 1570, however, a natural son (later known as Nanbu Harutsugu) was born to Harumasa. In 1576, Nobunao’s wife died. Nobunao relinquished his position as the designated heir and departed from Sannohe Castle, but Harumasa continued to distrust Nobunao. This situation evolved into a series of clashes between Harumasa and the Kunohe clan and conflict with Nobunao who led an alliance with Minami Nagayoshi and Kita Nobuchika.
In 1582, after the death by illness of Harumasa, an intense succession struggle broke out between the Minami clan and Nobunao (the former designated heir) on one side and Nanbu Harutsugu, the natural heir to Harumasa, on the other. Harutsugu momentarily succeeded Harumasa. After Harumasa’s funeral, however, Harutsugu was attacked and slayed while returning to Sannohe Castle. Under an alternate theory, Harutsugu died of smallpox, but given the timing of his demise less than three weeks after his father in the midst of a succession struggle, an intentional murder is a more compelling theory.
In the wake of this incident, the Nanbu family members and senior retainers hurriedly gathered for a grand council. In the discussions, Kunohe Sanechika (the husband of Harumasa’s second daughter and an influential figure in the family) and Nobunao (the formerly designated adopted heir to Harumasa) were named as potential successors. Strong support was voiced for Sanechika to become the successor, but Kita Nobuchika had earlier solicited the support of another powerful individual named Hachinohe Masayoshi of the Nejō-Nanbu clan so, in the end, Nobunao, who was recommended by Nobuchika and Minami Nagayoshi, was chosen as the successor. While returning to his territory, Masazane was very resentful that his younger brother, Sanechika, had been set aside and instead, Nobunao, who was a suspect in the killing of Harutsugu, succeeded Harumasa as the next head of the main branch of the Nanbu clan which Masazane served.
Revolt of Kunohe Masazane
In 1586, Masazane proclaimed himself as the head of the Nanbu family instead of Nobunao. This posture did not change even after the Oushū Retribution by Toyotomi Hideyoshi in 1590. Finally, in the first month of 1591,he refused to attend the congratulatory visit to the Nanbu clan marking the new year, and, in the third month, launched a rebellion with a contingent of 5,000 soldiers. This event is known as the Revolt of Kunohe Masazane.
As the original vanguard of the Nanbu army, the Kunohe forces were tough in battle. Moreover, some of the retainers of the Nanbu were ambivalent, believing that even if they prevailed in the family conflict, there would be no reward, causing Nobunao to struggle against the rebellion. Ultimately, Nobunao realized that he could not subdue the Kunohe forces on his own, so he sent his son, Nanbu Toshinao, and Kita Nobuchika as messengers to Hideyoshi to request in a meeting on 6/9 that Hideyoshi’s army subjugate them. Upon orders of Hideyoshi, Toyotomi Hidetsugu served as the commander-in-chief of an army led by Gamō Ujisato, Asano Nagamasa, and Ishida Mitsunari that commenced a march toward Oushū for the purpose of conquering the rebel forces of the Kunohe. In an army swelling to over 60,000 men, others joining the effort included Onodera Yoshimichi, Tozawa Masamori, Akita Sanesue, and Ōura Tamenobu.
On 9/1 of Tenshō 19 (1591), the Toyotomi army began attacks on the territory of the Kunohe. In a vigorous advance, on 9/2, the Toyotomi forces laid siege to Kunohe Castle in which Masazane and Sanechika were holed-up. Despite making a valiant defense, Masazane concluded that he could not win the contest and, after ending the resistance, on 9/4, surrendered to the Toyotomi army with the appearance of having entered the priesthood.
Having accepted their fate, Masazane and Sanechika were taken to the base of Hidetsugu, whereupon, while maintaining their composure, they were beheaded. The Kunohe family, including women and children, were slaughtered and the Kunohe clan decimated. The descendants of Masazane’s younger brother, Nakano Masazane, served, along with the Hachinohe and Kita clans, as chief retainers of the Nanbu family for generations, continuing as one of the group known as the Three Families.