Toeko Tatsuho was an artist representing Japanese contemporary paintings. Born in Nagano Prefecture in 1950, she finished the graduate school of Tokyo University of the Arts in 1974. In the 1970s, in response to Pop art and minimal art trends, Tatsuno produced controlled, inorganic prints and paintings with stripes and grids. From the 1980s, she focused on producing oil paintings and pursued abstract expressions through organic forms having decorative patterns and volumes. Although Tatsuno’s paintings are abstract, viewers feel as if the paintings were natural, three-dimensional space. Until her last years, Tatsuno kept on drawing colorful abstract paintings with rhythmically placed distorted orbits and rectangles.A diamond motif composed of rectangles appeared in Tatsuno’s works from the end of 1980s to the 1990s. In some of the last ones in these works, a range of rectangles were merged to constitute a diamond cluster. At the center of Work 90-9-80, Tatsuno drew a shadow-like three-dimensional diamond heavily painted in dark color as if to tower over the green space.