Butterfly-shaped fish

An unusual subject within Kasamatsu's catalogue, which is dominated by landscape and Tokyo cityscape rather than kacho-e — bird, flower, and nature studies. The title likely refers to a butterflyfish (chochouo) or a similarly patterned reef species whose fins suggest a butterfly's wings. Kacho-e prints traditionally place the subject against a plain or minimally inflected ground, and a fish print would adopt that convention while drawing on the Japanese tradition of fish painting that runs from the Maruyama-Shijo school through Hiroshige's "Large Fishes" series of the 1830s-40s. The print may belong to Kasamatsu's later sosaku-hanga period, when, working as his own carver and printer, he produced more experimental subjects than the shin-hanga production overseen by Watanabe Shozaburo in the 1930s and 40s typically encompassed.