The Hanakura Disturbance

Background — The Sudden Deaths of Imagawa Ujiteru and Hikogorō

On the 17th day of the 3rd month of Tenbun 5 (April 7, 1536), an unprecedented event occurred: Imagawa Ujiteru, the head of the Imagawa family, a shugo daimyō house of Suruga Province, and his younger brother Hikogorō, who was regarded as the designated successor, died suddenly in quick succession on the same day. No reliable source directly records the causes of death of the two men, and theories of epidemic disease, poisoning, and suicide have been proposed, but the cause of death has not been confirmed.

The Imagawa family was known as a prestigious shugo daimyō house descended from a branch of the Ashikaga shogunal family, and it governed both Suruga and Tōtōmi Provinces. With the sudden deaths of Ujiteru and Hikogorō, this prestigious house was left without a successor. Ujiteru had no legitimate male heir, and the clan would soon split into two power blocs over who among Ujichika's sons, several of whom had entered the priesthood, should become the next head. The sudden death of the head of a shugo daimyō house is a situation that readily invites division within the clan and intervention by outside forces, and the Hanakura Disturbance is today discussed as a typical example of exactly this.

Regency of Jukei-ni and the Situation within the Imagawa Clan

At the time his father, Imagawa Ujichika, died in the 6th month of Daiei 6 (1526), Ujiteru was only 14 years old. For this reason, Jukei-ni, Ujichika's principal wife, issued official documents under her own seal, which reads 'Ki,' and is known to have effectively managed the affairs of state of the Imagawa house for roughly two years, until Ujiteru reached the age of sixteen. Of the 25 surviving documents known to have been issued by Jukei-ni, 13 date from Ujiteru's period, which suggests the extent of her political influence within the clan. It is also thought that Jukei-ni played a certain role at this critical juncture, when a successor had to be chosen after the sudden deaths of Ujiteru and Hikogorō. Jukei-ni, who had married into the Imagawa house during the time of Ujichika, is said to have come from the Nakamikado family, a Kyoto court noble house, and is known as a figure of considerable weight in the introduction of court culture to Suruga and in diplomacy.

The Two Camps Contending for the Headship

The two candidates named for the headship were Senkaku Shōhō (the future Imagawa Yoshimoto), the fifth son of Imagawa Ujichika, who had entered Zentoku-ji temple in Suruga, and Genkō Etan, a son born to a concubine, who had entered Henjōkō-ji temple in Hanakura. It is said that even during Ujichika's lifetime, Shōhō held a higher position in the line of succession than Etan. Taigen Sessai, a Rinzai Zen monk who had served as Shōhō's tutor, and Imagawa retainer Okabe Chikatsuna supported his candidacy, and Hōjō Ujitsuna of Sagami Province also came to back him.

By contrast, Etan was backed by the Fukushima family, a senior Imagawa retainer house and the family of Etan's mother. Centering on Fukushima Echizen-no-kami and Fukushima Yashirō, they brought Etan into Hanakura Castle and took a stand against Shōhō. The Fukushima family held a certain degree of power within the Imagawa clan, and by backing Etan as maternal relatives, they appear to have sought to maintain their own influence. Etan himself had entered the priesthood and served as the chief priest of Henjōkō-ji, so he too had been a monk until he was pulled into the dispute over the succession. This shared circumstance with Shōhō, who had entered the priesthood at Zentoku-ji, is notable. In Sengoku-period daimyō houses, it was often customary to place sons of low succession rank in temples in advance. The brothers Shōhō and Etan had been placed in the priesthood under this custom, but the emergency of the main line of the house coming to an end unexpectedly called them back into secular life as candidates for the headship.

Uprising and the Struggle over Sunpu

On the 24th day of the 5th month of Tenbun 5 (June 12, 1536), Jukei-ni, seeking to resolve the situation, attempted to persuade Fukushima Echizen-no-kami, but her efforts ended in failure. The following day, the 25th (June 13), the two sides finally took up arms against each other at Sunpu, and Fukushima Echizen-no-kami withdrew to Kunō Castle. The fighting then spread to Yui Castle, Katanoue Castle, and Hanakura Castle, developing into an internal conflict that engulfed a broad area from central Suruga Province to the border with Tōtōmi Province.

Alarmed by the situation, Jukei-ni requested reinforcements from her backer, Hōjō Ujitsuna of Sagami, and in response a large force was dispatched to Suruga from the Hōjō side. With these reinforcements, Shōhō's faction gained military superiority and intensified its offensive against Etan's side. The Imagawa and Hōjō houses had built up ties of kinship and alliance since the time of Ujichika, and this request for reinforcements and their dispatch was also an event that again showed how deep the connection between the two houses was.

The Fall of Hanakura Castle and the End of Genkō Etan

On the 10th day of the 6th month of Tenbun 5 (June 28, 1536), Okabe Chikatsuna, on Shōhō's side, attacked and captured Katanoue Castle. Riding the momentum of this victory, he then launched a full-scale assault on Hanakura Castle, the last stronghold of Etan's faction. Hanakura Castle soon fell. Etan escaped the castle and fled to Fumon-ji temple in Setoya in Suruga Province (present-day Fujieda, Shizuoka Prefecture), but he was driven into a corner there and took his own life, ending his life at that place. The principal members of the Fukushima family, who had supported Etan, also lost nearly all of their power in this fighting. Hanakura Castle, Yui Castle, and Katanoue Castle are all located in the central part of present-day Shizuoka Prefecture, and the fact that the battle lines extended east and west across Sunpu shows the scale of the disturbance. Fumon-ji temple in Setoya, where Etan ended his life, is located in the mountains further inland from Hanakura Castle. That Etan was driven to such a remote place before meeting his end shows how thorough the purge carried out by Shōhō's side was.

Result — Imagawa Yoshimoto's Succession and the Debate over Jukei-ni's Position

With Etan's suicide, the succession struggle, which had lasted roughly three months, was brought to a close. Shōhō, the victor, formally succeeded to the headship of the Imagawa house under the name 'Yoshimoto,' which included a character granted to him by the shogun Ashikaga Yoshiharu. This series of internal conflicts was later called the 'Hanakura Disturbance,' after the name of Hanakura, the place where the two sides had fought.

Scholars are divided over Jukei-ni's position in this disturbance. While it is widely held that she returned Shōhō to lay life and backed him as Yoshimoto, an alternative theory has also been presented: based on a passage in the contemporary record Kōhakusai-ki and on interpretations of the circumstances surrounding Hikogorō's death, it holds that Jukei-ni was in fact on the side of Genkō Etan, not that of her own son Yoshimoto. No definitive conclusion has been reached. The name of the disturbance is also sometimes written inconsistently in later compilations and local traditions, with the place name spelled in two different ways that are both read Hanakura. Both forms, however, share the common origin in the name of Hanakura in Suruga Province, where the two sides fought.

Influence on Subsequent Events

Yoshimoto, who secured his position through the Hanakura Disturbance, relied on Taigen Sessai in managing his domain and worked to build an alliance with the Takeda clan of Kai Province. The historian Marushima Kazuhiro has suggested that Yoshimoto's choice of an alliance with the Takeda may have been intended as a check against Hōjō Ujitsuna, who had backed his succession. However, this approach toward the Takeda contributed to the worsening of relations with Ujitsuna and was one of the underlying causes of the later Katō Ichiran, in which Suruga, Sagami, and Kai became entangled.

Having consolidated control of the clan through the Hanakura Disturbance, Yoshimoto went on to expand his power toward Mikawa and Owari, building the peak of Imagawa power that would lead to the Battle of Okehazama. Taigen Sessai, who continued to support Yoshimoto, also demonstrated his skill as a diplomatic monk and is widely known for his deep involvement in the establishment of the alliance among the Imagawa, Takeda, and Hōjō clans (the so-called Kōsō-Sun tripartite alliance). Sessai's presence at Shōhō's side during the Hanakura Disturbance thus remained an important factor that shaped the diplomatic course of the entire Imagawa house thereafter. As the greatest internal dispute over succession in the history of the Imagawa house, the Hanakura Disturbance continues to attract the interest of researchers today as a case showing both the risk posed by the sudden death of a head of a Sengoku daimyō house and the extent to which the positions taken by regents and maternal relatives could shape the political outcome.