Operation Cherry Blossoms at Night 27 August 2017, Pepino A4 (29,7 x 21,0 cm) Watercolor, acrylic color, ballpoint pen, felt-tip pen, correction fluid and color pencil on paper i Operation Cherry Blossoms at Night was a Japanese plan to wage biological warfare upon civilian population centers in Southern California in the United States during the final months of World War II. Tags: Japan, cherry, blossom, sakura, hanami, war, warfare, night 43 / 779