Samurai Commander Hosokawa Sumimoto died on this day, June 24 in 1520.
Typical of an elite Sengoku samurai warrior, Hosokawa Sumimoto’s life reads like a drama series. A member of the Awa Hosokawa clan (modern-day Tokushima Pref. Shikoku) Sumimoto was born in 1489 to Hosokawa Yoshiharu, who served as the governor of Awa Province, but died when Sumimoto was six years old. Sumimoto was raised by his grandfather Nariyuki before being adopted by the childless Hosokawa Masamoto, Deputy Shogun to the Ashikaga Shogunate.
The head of the main Hosokawa clan, Hosokawa Masamoto, was a key figure in the shogunate as Kanrei (regent) at the time, but because he remained single and had no children, Masamoto adopted three sons. The first was Hosokawa Sumiyuki of the Kujo Hosokawa clan, then Sumimoto, and later Hosokawa Takakuni. Sumiyuki, being the first son was to be heir, however the adopted father and son did not get on well together, and so in 1503 Sumiyuki was demoted, and in his place it was decided that Sumimoto would become his successor, leading to animosity between the brothers. Sumimoto, as Masamoto's successor, took over the duties of Settsu Shugo, governor, in place of Masamoto from 1506. Later that year he attacked Isshiki Yoshiari in Tango Province with Sumiyuki at Masamoto's command but was defeated.
Although Sumimoto had been selected as Masamoto's successor, shortly after adopting Sumimoto, Masamoto adopted yet another son, Takakuni, the son of Hosokawa Masaharu, from the Noshu branch of the Hosokawa clan, creating a situation in which there were three successor candidates.
Masamoto then claimed he did not want Sumimoto as his heir, and was in turn threatened by Miyoshi Yukinaga’s army who supported Sumimoto. The same problem arose when Masamoto and Sumiyuki had a dispute, and yet another successor was chosen, which led to Sumiyuki and his retainer Kozai Motonaga attacking Masamoto's home on August 1, 1507, and killing his adoptive father while he was taking a bath. The next day, the pair then attacked the 19-year-old Sumimoto’s residence, who fled to Aoji Castle in Omi Province, (Shiga Prefecture) seeking refuge with Yamanaka Tametoshi in Koka. In revenge, Miyoshi Yukinaga, a powerful Hosokawa clan retainer, raised an army and attacked and killed Sumiyuki. This allowed Sumimoto to petition the Shogun Ashikaga Yoshizumi and return to claim his rightful position as the Hosokawa clan leader.
However, because Sumimoto was still young, the power of his supporter, Miyoshi Yukinaga, began to grow, bringing Sumimoto into conflict with Yukinaga. Sumimoto considered returning to Awa at one point but was persuaded by Shogun Ashikaga Yoshizumi to remain.
Sumimoto and his other half-brother, Hosokawa Takakuni were supporters of the 11th Ashikaga Shogun, Yoshizumi, a puppet who had been raised to the position of Shogun in 1493 by the half brother’s shared step-father, by ousting the 10th Shogun, Yoshitane. When the former Shogun, Yoshitane, who had been exiled to Suo Province was informed of the troubles in Kyoto, he raised an army supported by Ouchi Yoshioki and in 1508 began to march on Kyoto in an attempt to reclaim his rightful position. Sumimoto reached out and tried to make peace with Ouchi Yoshioki, but the arrangement broke down when his adopted brother Hosokawa Takakuni, the third of Masamoto's adopted sons and who had cooperated in the attack on elder brother Sumiyuki, defected to the Ouchi.
However, as conflict began between Ouchi Yoshioki and Yoshitada, Sumimoto and Miyoshi Yukinaga invaded Kyoto in 1509, but were defeated by a counterattack from Takakuni and Ouchi Yoshioki resulting in the Battle of Nyoigatake. Sumimoto and Yukinaga then fled to Awa.
According to an entry in the Fumon Monogatari war chronicles, Takakuni's defection is said to have been the result of resentment against Sumimoto's favoring of Miyoshi Yukinaga and Takabatake Naganobu, who had been his close aides since the Awa period, over his own — although adopted— family.
The Hosokawa clan — now facing internal turmoil — tried to depose Sumimoto and support Takakuni. As Takakuni gained supporters, Sumimoto was forced into exile yet again, but made an attempt on Kyoto in 1511. Ashikaga Yoshizumi, along with his brother-in-law, Hosokawa Masakata, head of the Norimaya Hosokawa clan, his relatives Hosokawa Mototsune the Shugo of Izumi, Hosokawa Naoharu, Shugo of Awaji, and Akamatsu Yoshimura the Shugo of Harima Province, attacked Fukai Castle (Battle of Fukai Castle) and Takao Castle (Battle of Ashiyagawara), and then invaded Kyoto, which led to the Battle of Funaokayama. However, Ashikaga Yoshizumi died of an illness just before this battle and his army was defeated in a counterattack from Ouchi Yoshioki, ending with Masakata being killed in action and the defeated Sumimoto fleeing to Settsu.
It seems that this military campaign was undertaken despite the opposition of his grandfather, Nariyuki, and Miyoshi Yukinaga, and it has been pointed out that Yukinaga may have been trying to collude with Takakuni's camp in order to preserve the Awa Shugo clan. However, immediately after this campaign, Nariyuki and Yukimochi died one after the other, causing chaos in Awa. Sumimoto and Miyoshi Yukinaga reconciled and set out to restore order to Awa and regain control of Sanuki Province.
Believing that both Kyoto and the Shogunate were now in safe hands, Ouchi later returned to his lands in Yamaguchi. Sumimoto secretly raised an army with Miyoshi Nagateru and took the lull in security as an opportunity to advance on Kyoto again, however they were routed by Takakuni and the Rokkaku clan of Omi (Shiga Prefecture), who captured Nagateru and forced him to commit seppuku. Sumimoto had fallen ill during the advance, and after Nagateru’s death, quickly returned home to Shozui Castle in Awa where he died shortly after. Sumimoto was 31 years old.
After Sumimoto's death, his eldest son, Harumoto, inherited the family headship. Harumoto with Miyoshi Yukinaga's grandson, Motonaga, later defeated Takakuni, but he in turn was defeated in a battle by Takakuni's adopted son, Ujitsuna (Masakata's step-grandson), during which Motonaga's son, Nagayoshi, sided with Ujitsuna. The Hosokawa clan’s internal strife, and political infighting would continue for many years to come.