Shiryōkaku (四稜郭) (literally, "four-point fort") is a fort in the city of Hakodate in southern Hokkaidō, Japan. It was constructed in April 1869, during the Battle of Hakodate, three kilometres to the northeast of Goryōkaku by two hundred soldiers of the former Tokugawa shogunate and a hundred local villagers, likely under the direction of Ōtori Keisuke.[1] Shiryōkaku has four bastions , and is sometimes known as the "butterfly fort" as opposed to the "star fort".[1] | ||||||