普鲁士蓝
Beginning in the 1820s, Prussian blue was imported into Japan through the port of Nagasaki. It was called "bero-ai", or Berlin blue, and it became popular because it did not fade like traditional Japanese blue pigment, "ai-gami", made from the dayflower. Prussian blue was used by both Hokusai, in his famous wave paintings, and Hiroshige.