Hosokawa Tadaoki, retainer of Oda Nobunaga and Toyotomi Hideyoshi
A conflict between Hosokawa Katsumoto, the fifth Kanrei, and his father-in-law Yamana Sōzen, over the shogunate's succession, sparked the Ōnin War, which led to the fall of the shogunate and a period of 150 years of chaos and war, known as Sengoku. Following the fall of the Ashikaga shogunate, which was based in Kyoto, control of the city, and thus obstensibly the country, fell into the hands of the Hosokawa clan (who held the post of Kyoto Kanrei - Shogun's deputy in Kyoto) for a few generations.
Katsumoto's son, Hosokawa Masamoto, held power in this way at the end of the 15th century, but was assassinated in 1507. After his death, the clan became divided and was weakened by internecine fighting. What power they still had, however, was centered in and around Kyoto. This gave them the leverage to consolidate their power to some extent, and came to be strong rivals with the Ōuchi family, both politically, and in terms of dominating trade with China. The Hosokawa remained in Kyoto for roughly one hundred years, fleeing the city when it was attacked by Oda Nobunaga.
Hosokawa Shigekata, mid-Edo era daimyo of the Kumamoto domain
Hosokawa Gyōbu mansion
The Hosokawa of Kokura (later Kumamoto) became the "main" line of the Hosokawa clan during the Edo period. Hosokawa Gracia, the wife of Hosokawa Tadaoki, was one of the most famous samurai converts to Christianity; she was also the daughter of Akechi Mitsuhide.
Though the Hosokawa domain was far from the capital, on Kyūshū, they were among the wealthiest of the daimyo. By 1750, Higo was one of the top producers of rice, and was in fact counted as a standard by the Osaka rice brokers. The domain suffered from serious economic decline after that, as most domains did, but the sixth lord, Hosokawa Shigekata (1718–1785, r. 1747-1785) instituted a number of reforms which turned the situation around. He also founded a Han school, Jishuukan, in 1755. In later years, it produced many scholars such as Yokoi Shonan.
In 1787, the main family line descended from Tadatoshi became extinct with the death of the 7th lord, Shigekata's son Harutoshi (1758–1787; r. 1785-1787). He was succeeded by his distant cousin Narishige, the sixth Lord of Udo (1755-c1835, r. 1787-1810) a direct descendant of Tadatoshi's younger brother Yukitaka (1615–1645). In 1810, Narishige abdicated his title in favor of his elder son Naritatsu (1788–1826, r. 1810-1826), who succeeded as the ninth lord of Kumamoto. Naritatsu died without an heir in 1826, and was succeeded by his nephew Narimori (1804–1860, r. 1826-1860), the son of Naritatsu's younger brother Tatsuyuki (1784–1818), who was the seventh lord of Udo.
Following the death of Narimori in 1860, his elder son Yoshikuni (1835–1876, r. 1860-1871) succeeded him as the eleventh and final ruling lord of Kumamoto.
There were four major branches of the Hosokawa clan in the Edo period, each of which held the title of daimyo. Another two branches of the family, under the Nagaoka surname, served the Hosokawa of Kumamoto as karō. The residence of one of those families, Hosokawa Gyōbu mansion (細川刑部邸,Hosokawa Gyōbu-tei?), is still extant, and is a Tangible Cultural Property of Kumamoto Prefecture.
Following the abolition of the feudal class in 1871, the Hosokawa clan and its branches were made part of the new nobility in the Meiji era. The head of the main family line (Kumamoto) was given the hereditary title of marquis (kōshaku), while the heads of the secondary branches became viscounts (shishaku); the titles became obsolete in 1947. The present head of the main family line, Morihiro Hosokawa, former Prime Minister of Japan, is a descendant of the Hosokawa of Kumamoto.
14. Moritatsu, 14th Hosokawa family head, 3rd Marquess, 2nd Baron (1883-1970; 2nd Baron Hosokawa 1898, 14th Hosokawa family head 1914-1970 and as the 3rd Marquess 1914-1947, titles abolished in 1947). He had a son:
15. Morisada, 15th Hosokawa family head (1912-2005; family head 1970-2005). He had a son:
16. Morihiro, 16th Hosokawa family head (1938- ; family head 2005-). Prime Minister of Japan 1993-1994. He has one son.
IX. Naritatsu, 9th Lord of Kumamoto (1788-1826; r. 1810-1826)