Lake Kussharo
 Lake Kussharo (屈斜路湖 Kussharo-ko) is a caldera lake in Akan National Park eastern Hokkaidō Japan. As with many geographic names in Hokkaidō the name derives from the Ainu language. It is the largest caldera lake in Japan in terms of surface area and sixth largest lake in Japan. It is also the largest lake in Japan to freeze over completely in winter.The lake’s central island Nakajima is a composite volcano.