

Sadamasa Motonaga was born in 1922 in Ueno, Japan. He graduated from commercial school in Ueno, Mie Prefecture, in 1938, aspiring to become a manga artist. He began painting figurative and landscape works on canvas under the guidance of Mankichi Hamabe.
When he moved to Kobe in 1952, he experimented with abstract painting and made sculptures using a combination of natural and industrial materials such as wood, water and plastic. In 1953, his work Kiiro no rafu (Yellow Nude) won the Holbein Prize at the Ashiya City Art Exhibition, catching the attention of Jiro Yoshihara.
Two years later, in 1955, Yoshihara invited Motonaga to join the Gutai Art Association, a group of radical postwar artists in Japan, and participate in the Modern Art Outdoor Experimental Exhibition to Challenge the Midsummer Sun in Ashiya Park. On this occasion, Motonaga created his most famous site-specific installation Work (Water), made from vinyl tubes filled with colored water and hung from tree branches.
He was then invited by the Japan Society to spend a year in New York from 1966 to 1967, followed by a period in Europe. As a result of this time abroad, inspired by the traditional tarashikomi technique, in which layers of paint are allowed to settle unevenly, he developed a technique using acrylic paints and the airbrush. This new technique led in 1970 to a more distinctive style of intense, vividly colored, saturated paintings with humorous titles.
Returning to Japan, he left the Gutai group in 1971 and began making silkscreens, tapestries, chair designs, and illustrations for children’s books. During his lifetime, he received awards for excellence at the Japan Contemporary Art Exhibition and other numerous awards and cultural merits. In 2011, the Guggenheim in New York commissioned him to reconstruct the work Water for the 2013 exhibition Gutai: Splendid Playground. Sadamasa Motonaga passed away in Kobe in 2011.