The Eishō Disturbance (Eishō no sakuran) refers to a succession struggle within the Hosokawa-Keichō family in combination with a competition in the Ashikaga family for the role of shōgun. The name of the disturbance derives from its occurrence during the Eishō era (1504-1521).
The events were triggered by the assassination of Hosokawa Masamoto, the kanrei, or deputy shōgun, of the Muromachi bakufu in 1507 – an event referred to as the Lord Hosokawa Incident (Hosokawa-dono no hen). His death led to internal discord regarding his successor to the Hosokawa-Keichō family – the main branch of the Hosokawa clan. This branch served as hereditary military governors of Settsu, Tanba, Sanuki, and Tosa provinces in addition to the role of deputy shōgun for the Muromachi bakufu in Kyōto. In the background, the retainers of the Hosokawa-Keichō family in the Kinai were opposed to the Miyoshi clan of Awa Province who supported Hosokawa Sumimoto, one of Masamoto’s adopted sons.
Furthermore, the former shōgun, Ashikaga Yoshitane, had designs to overthrow the current shōgun, Ashikaga Yoshizumi, and reclaim his position. Based on the support of others in the Kinai, Hosokawa Takakuni (another one of Masamoto’s adopted sons) became the successor to Masamoto one year after Masamoto’s assassination, while Yoshitane reclaimed the role of shōgun. Meanwhile, Yoshizumi and Sumimoto, along with their supporters in the Miyoshi clan, aimed to restore their authority, resulting in a prolonged series of military clashes in the Kinai known as the Conflict between the Hosokawa (Ryō-Hosokawa no ran). This conflict between two branches of the Hosokawa clan and their respective allies ran approximately from 1509 until 1531.
Details of the conflict
The three adopted sons of Hosokawa Masamoto
In 1493, Hosokawa Masamoto, the twenty-seventh lineal deputy shōgun of the Muromachi bakufu deposed Ashikaga Yoshiki (later known as Yoshitada and then Yoshitane – the tenth shōgun), and supported Ashikaga Yoshitō (later known as Yoshitaka and then Yoshizumi – the eleventh shōgun) in a coup d’ètat known as the Meiō Political Incident (Meiō no seihen). At the time, Masamoto wielded absolute authority, but owing to his devotion to an austere form of Japanese Buddhism known as shugendō that, among other sacrifices, prohibited relations with women, he did not have any children of his own, and did not have siblings, so there was no successor to Masamoto in the Hosokawa-Keichō family. As a result, Masamoto adopted three sons, including Hosokawa Sumiyuki (the youngest son of Kujō Masamoto, who held the elite title of kanpaku, or Chief Advisor to the Emperor), Sumimoto (originating from a Hosokawa family serving as shugo, or military governors, of Awa Province), and Takakuni (originating from a cadet family of the clan known as the Hosokawa-Yashū). This situation gave rise to conflict over the issue of succession.
During the extended conflict known as the Ōnin-Bunmei War (Ōnin-Bunmei no ran) that devastated much of Kyōto and its environs between 1467 to 1477, numerous daimyō families were weakened after fighting over issues of succession. Within the Hosokawa family, Hosokawa Katsuyuki received some support as the potential successor to Hosokawa Katsumoto, but, in the end, Masamoto became the designated successor based on his status as Katsumoto’s eldest son. In the era of Masamoto, the Hosokawa family was able to strengthen its position in the Muromachi bakufu. However, owing to the absence of a natural successor, the Hosokawa-Keichō family experienced the turmoil of a dispute over succession a generation after other daimyō families.
In 1506, Hosokawa Sumimoto, the military governor of Settsu, led forces from Awa to Kyōto. The confrontation between these forces from Awa and the Hosokowa-Keichō family deepened as a result of Masamoto’s increased reliance upon Miyoshi Yukinaga (the kasai, or head of family affairs) to manage military affairs along with senior retainers of the Keichō family (primarily kokujin, or provincial landowners, from the Kinai) who had supported Masamoto’s administration.
The assassination of Hosokawa Masamoto (Hosokawa-dono no hen)
Masamoto immersed himself in shugendō, frequently acting eccentrically and portraying himself as Tengu, a mythological creature in the view of believers. On 6/23 of 1507, while entering the bathroom in the residence in preparation to practice sorcery, he was murdered by a secretary from the Tokura clan upon the urging of retainers who supported Sumiyuki, including Yakushiji Nagatada, Kōzai Motonaga, and Takeda Magoshichi. This incident is known as the Lord Hosokawa Incident. The day after the killing, Nagatada led an attack against the residences of Sumimoto and Miyoshi Yukinaga, forcing Sumimoto to flee to Ōmi Province, and received Sumiyuki as the successor to the Hosokawa-Keichō family. On 6/26, Akazawa Tomotsune, who, upon earlier orders of Masamoto, was attacking Isshiki Yoshiari of Tango Province, attempted to have his army retreat to Kyōto, but was forced to kill himself after being subject to a counterattack by Yoshiari and Ishikawa Naotsune, a kokujin from Tango. Tomotsune’s adopted son, Akazawa Nagatsune, escaped safely and came under the command of Sumimoto.
One more of the adopted sons, Hosokawa Takakuni, consulted with Hosokawa Masakata (a district-level shugo, or military governor, in Settsu Province), Hosokawa Hisaharu (the military governor of Awaji Province), and Hatakeyama Yoshihide (the military governor of Kawachi Province), and agreed to have Sumimoto become the successor to Masamoto. On 7/28, Yakushiji Kuninaga (the son of Yakushiji Motokazu who had earlier been killed by Motokazu’s younger brother, Yakushiji Nagatada), captured Nagatada’s home base at Ibaraki Castle. On 7/29, Hosokawa Takakuni captured Kōzai Motonaga’s home base of Arashiyama Castle. On 8/1, Miyoshi Yukinaga and kokujin from the Kōka District of Ōmi to where he had earlier fled quickly returned to Kyōto, and together with the forces under Takakuni, attacked and toppled the last residence held by Sumiyuki known as Yūshoken in Kyōto, causing Sumiyuki to take his own life. On 8/2, Sumimoto met the shōgun, and inherited the Hosokawa-Keichō family.
The confrontation between Sumimoto and Takakuni
Following his ouster as shōgun in the Meiō Political Incident, in 1499, Ashikaga Yoshiki depended upon Ōuchi Yoshioki of Suō Province, the most powerful sengoku daimyō in western Japan for protection. The Muromachi bakufu became concerned that the assassination of Masamoto in the sixth month of 1507 would invite a response from Yoshioki, whereupon the officials issued an edict to express the intent of the Emperor known as a rinji ordering kokujin in Aki and Iwami provinces to overthrow Yoshioki. However, by the end of the year, Yoshioki raised an army in Suō to march to Kyōto in support of Yoshiki. The contingent departed from Yamaguchi, passing the new year in the village of Tomo in Bingo Province and waiting for the opportune time to advance on the capital.
Around this time, Hosokawa Takakuni gained supporters in the Kinai to oppose the despotic actions of Miyoshi Yukinaga. Sumimoto approached Takakuni for settlement negotiations with Yoshioki, but instead Takakuni fled to Iga Province, joined with Yoshiki and Yoshioki, and allied with kokujin from Kinai including Itami Motosuke and Naitō Sadamasa.
In the fourth month of 1508, Sumimoto and Yoshizumi fled in succession to Ōmi Province, while Takakuni entered Kyōto. At the end of the fourth month, Yoshiki and Yoshioki arrived at the metropolis of Sakai in Izumi Province, whereupon Takakuni came to meet them and inherited the role as head of the Hosokawa-Keichō family. In the sixth month, Yoshiki traveled from Sakai to Kyōto and reclaimed his position as shōgun. Symbolic of his role as head of the Hosokawa-Keichō family, Takakuni was conferred the title of Master of the Western Capital Office, while Yoshioki was awarded the titles of Master of the Eastern Capital Office, assistant deputy shōgun, and military governor of Yamashiro.
During a period of one year (from mid-1507 to mid-1508), the head of the Hosokawa-Keichō family transferred from Masamoto to Sumiyuki to Sumimoto to Takakuni. Moreover, by this time, the political authority of the role of kanrei, or deputy shōgun, had been lost so the role could no longer be assured to whomever became head of the family. The seat had been vacated ever since Masamoto assumed the position in 1494.
The turmoil associated with these events set the stage for over two decades of conflict between Hosokawa Takakuni and his supporters on one side against forces from Awa Province including Hosokawa Sumimoto, his son (Hosokawa Harumoto), and the Miyoshi clan. This extended conflict is known as the Conflict between the Hosokawa.