The Mitsui Memorial Museum houses a collection of Japanese and Oriental artwork collected over the course of the Mitsui family's 350-year history since the Edo period (1603-1868) and was established in October 2005 when the Mitsui Bunko Annex (Nakano Ward, Tokyo) was relocated to Nihonbashi, an area closely associated with the Mitsui family and the Mitsui Group. The Mitsui Main Building, where the Mitsui Memorial Museum of Art is located, is a stately Western-style building representing Japan in the early Showa period and is designated as a National Important Cultural Property.

The museum currently holds approximately 4,000 works of art and 130,000 stamps, of which 6 are National Treasures, 75 are Important Cultural Properties (including one in the museum's possession), and 4 are Important Art Objects. The collection includes tea ceremony utensils, paintings, calligraphy, swords, Noh masks, Noh costumes, furnishings, and a wide variety of other objects, mainly donated by the Kita (Soryo), Shinmachi, Muromachi, Isarako, and Honmura-cho houses of the eleven Mitsui houses. Stamps were also donated by the Minami family, as well as the collection of Tadashi Masatani, former president of Daicel, which is not part of the Mitsui family. In addition, the museum has received gifts of dolls from the Asano family, a member of the Mitsui family, and swords from the Takashi family, which is related to the Mitsui family by marriage.

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