Born in Ibaraki, Japan in 1931, Ay-O studied fine art at Tokyo University of Education (now the University of Tsukuba) and emerged as a leading avant-garde artist. In 1958, he moved to the United States and was based in New York, where he became an active member of Fluxus, the international avant-garde art movement.

Known for his vivid, rainbow-centered aesthetic, Ay-O earned the nickname “Rainbow Man.” His diverse body of work spans painting, printmaking, performance, and happenings, and has been highly acclaimed both in Japan and internationally.

- Biography
1953 Joined the Democratic Artists Association (Japan)
1954 Graduated from the Faculty of Fine Arts, Tokyo University of Education
1955 Co-founded Jitsuzaisha with Masuo Ikeda and others
1958 Moved to New York and began his avant-garde artistic activities
1961 Introduced by Yoko Ono to George Maciunas and officially joined Fluxus
1964 Presented the “Rainbow Happening” series at Fluxus events, including at Carnegie Recital Hall
1966 Represented Japan at the 33rd Venice Biennale; gained international recognition for his rainbow works
1970 Created “Rainbow Tactile Room” for Expo ’70 in Osaka
1971 Represented Japan at the 11th São Paulo Biennial; awarded the Bank of Brazil Prize
1987 Executed a project installing a 300-meter rainbow banner on the Eiffel Tower, Paris
1995 Received the Medal with Purple Ribbon (Japan)
2006 Held the retrospective exhibition “Over the Rainbow: Ay-O Retrospective 1950–2006” at Fukui Fine Arts Museum and other venues
2012 Held the exhibition “Ay-O: Over the Rainbow Once More” at the Museum of Contemporary Art Tokyo and other venues

His works are included in major museum collections worldwide, including:
The Museum of Modern Art (MoMA), New York
The British Museum, London
The National Museum of Art, Osaka
and many other international and Japanese institutions.