Yasuo Sumi (b.1925) joined the Gutai art association in 1955. He participated in all the Gutai exhibitions. While painting and performing Sumi always wore a pair of geta (wooden Japanese shoes). Known for using soroban (Japanese abacus) as well as vibrator and a bangasa (traditional umbrella) as painting techniques. Sumi used the sorobans together with Japanese ink to create straight and curved lines on papers and canvas.