Named for one of the lakes in Akan National Park, which is located in eastern Hokkaido, a one-hour drive from Kitami and Kushiro {see planets  (3720),  (3785), and  (4096), respectively}. The caldera lake is 20 km in circumference, covers an area of 19.6 square km and has a maximum depth of 212 m. No rivers flow into or out of the lake, which is one of the most transparent in the world, although its surface is almost always shrouded in fog. (M 15428) _ _.