Born 1933 in Tokyo, based in Tokyo.

A self-taught artist, Okamoto has been exhibiting in independent shows since the mid-1950s, debuting as a flag-bearer for avant-garde painting that rejected hitherto mainstream painting expression. Okamoto's style is characterized by a combination of spare lines bearing no trace of brushstroke, and simple, vibrant coloring, and he has consistently and industriously turned out paintings that are sharply critical of society and culture and include a series of unique characters that feature repeatedly in his work. His 2011 solo show "The Big Bomb at 25:00" at the Shoto Museum of Art in Tokyo had a war theme. Especially noteworthy was the massive 《 Rolling Cherry Blossoms: The Big Bomb for Tokyo 》 depicting the devastating 1945 air raids over Tokyo that he witnessed as a boy, and which he had made a conscious decision not to portray until prompted to do so by the 9/11 attacks on New York in 2001. This canvas with the same motifs persistently repeated simultaneously contains various pieces of text, names of events etc. from history. Two experiences coexist in the viewer: that of being mesmerized by the painted motifs and their detail, and the intellectual experience of reading the text, akin to the experience of reading.