Lake Toya, the caldera lake situated in the southwestern Hokkaido, belongs to Shikotsu-Toya National Park. The lake facing Mt.Usu , one of the most active volcanoes, with repeated eruptions on a cycle of between 30 and 50 years. Its most recent eruption was in 2000.
Lake Toya is an ice-free lake. It never freezes, even in winter when the temperature falls quite drastically.
There are big and small four islands called Nakajima in the middle of the lake .
