Lake Shikotsu in Hokkaido
Lake Shikotsu is located near Chitose in Hokkaido. This lake is the second deepest lake in Japan. The average depth is 265 meters and the deepest point is 363 meters. One interesting thing about this lake is the water temperature stays the same virtually all year long. It is also the northernmost ice-free lake in Japan. I highly recommend visiting Hokkaido. If you're visiting from outside of Japan, be sure to bring your International Driver's license and rent a car. Having a car in Hokkaido makes sight seeing much easier. The navigation systems in most rent a cars are bilingual as well, so that is very helpful for non-Japanese speakers.
Below are some photos in the nature reserve of the Japanese wildlife that is present in Hokkaido.