- Established: 1950, Hosokawa Moritatsu
- Japanese: 永青文庫 (Eisei Bunko)
The Eisei Bunko is the private archive of the Hosokawa clan collections. Established as an incorporated foundation (zaidan hônin) in 1950 by Hosokawa Moritatsu, it is based in a portion of the family's former estate in the Mejirodai area of Tokyo; a portion of the estate's gardens are maintained nearby as the Higo-Hosokawa Garden. The archive takes its name from the "ei" of Eigen-an, a branch temple of Kennin-ji (the family temple of a branch of the Hosokawa descended from Hosokawa Yoriari), and the "sei" of Seiryûji castle, home of Hosokawa Fujitaka.
The archive was opened to public visitors in 1972, and was officially registered as a museum the following year. The Eisei Bunko Museum was reorganized as a public interest institution (kôeki zaidan hônin) in 2010. It is housed in the former administrative building for the Hosokawa family estate, built in the late 1920s or early 1930s. The organization hosts four regular exhibits a year at this Tokyo location, as well as exhibits in a dedicated space at the Kumamoto Prefectural Art Museum. The archive also works closely with researchers at several institutions in Kumamoto and Tokyo, providing access to documents and artifacts in the collection in order to aid in research on Japanese art and history.
The collection includes eight National Treasures and 31 Important Cultural Properties, ranging from ancient bronze mirrors and Buddhist sculptures to ceramics and other tea wares, paintings, arms & armor, and historical documents. A very few of the treasures in the collection include:
- A bronze Buddhist sculpture from the Liu Song dynasty, dated 437 (Important Cultural Property)
- A chaire (tea jar) previously owned by Sen no Rikyû and given as a gift from Shogun Tokugawa Hidetada to Hosokawa Sansai. Originally made in Song or Yuan dynasty China
- A flower vase made by Sen no Rikyû from a section of bamboo
- A letter from Emperor Go-Fukakusa to Emperor Fushimi, dated 1292 (Important Cultural Property)
- Haseo sôshi - a Kamakura period painting depicting the story of the Heian period figure Ki no Haseo (Important Cultural Property)
- The so-called "Hosokawa Mirror" (National Treasure) - a bronze mirror excavated from a site near Luoyang and dating to China's Warring States Period
- Kuroki neko - a painting of a black cat by Hishida Shunsô, which appeared in the 4th Bunten competition in 1910 (Important Cultural Property)
- A porcelain jug decorated with peonies, from the Southern Song Dynasty (Important Cultural Property)
- Shigure raden kura (National Treasure) - a lacquerware saddle decorated with mother-of-pearl inlay
- Numerous works by Kumamoto domain court painter Sugitani Yukinao
- Suit of armor (yoroi) said to have been worn by Hosokawa Yoriari in battle in 1358 (Important Cultural Property)
- Eisei Bunko Museum pamphlet available on-site.
- General overview pamphlet, Kumamoto Prefectural Museum of Art.