Born in Mie in Japan in 1922, Motonaga was self-taught artist who became close to the Gutai group of artists after meeting Yoshihara Jiro. Like all the members of the group, he sought new means of expression, unprecedented forms, brilliant colours and free experimentation. During a Gutai group exhibition in America, he moved to New York for a year, radically changing his style. He began painting in a traditional way, using acrylic colours and aerogrammes. His artistic practice was inspired in part by the Japanese technique called tarashikomi: he applied layers of liquid paint that were absorbed into the canvas in an irregular way. After returning to Japan, he became interested in form, which for him, comes before colour, and he began printing on silk panels and creating illustrated books, becoming one of the most popular contemporary Japanese artists. He died in 2011.
His works have previously been shown at the Hiroshima City Museum of Contemporary Art in 2003, at the Mie Prefectural Art Museum in 2009 and at the Venice Biennale in 1993 and 2009.