Idemitsu Museum of Arts

The Idemitsu Museum of Arts is a private museum that houses East Asian and Japanese art collected by Idemitsu Sazō (1885–1981), founder of Idemitsu Kosan. It is located on the 9th floor of the Teigeki Building in Marunouchi, Chiyoda-ku, Tokyo, and has been closed for an extended period since December 2024 due to the rebuilding of the building. Since opening in 1966 (Shōwa 41), it has held about 10,000 objects, centered on Japanese, Chinese and Korean ceramics and calligraphy and painting, including works by Sengai, as well as lacquerware and metalwork. Its collection includes many National Treasures and Important Cultural Properties, and it is highly regarded at home and abroad as one of Japan's leading corporate collections.

Among the swords, a tachi signed Kunimura is designated an Important Cultural Property.

From the 9th-floor lobby, visitors could look out over the adjacent Imperial Palace Outer Gardens (Kōkyo Gaien).

Exhibitions of works from the collection have continued during the closure. The exhibition “Jewels of the Idemitsu Collection Seen at Geidai” (Geidai de miru shugyoku no Idemitsu korekushon) is scheduled to be held at the University Art Museum of the Tokyo University of the Arts from 27 March to 23 May 2027, as a commemorative exhibition for the museum's 60th anniversary.