“Onneto” is a lake located on the westernmost point of Akan Mashu National Park which means “old big lake” in Ainu language. The surface of the lake changes its colors to clear blue, emerald green, dark blue and so on depending on the wind direction, weather, and where the visitor is, so it is called “Goshiki-numa” (pond of 5 colors). A popular spot with an amazing view is located on the west side of Onneto called Lakeshore Observatory Deck. Visitors can enjoy the whole surrounding view of the beautiful Mount Meakan and Mt. Akan-Fuji. Wind starts to blow and waves start to form before noon so if you want to see the beautiful colors of the lake surface or the reflection on the water, it is recommended to visit first thing in the morning. There are walking paths near the lakeshore and it is a perfect place to enjoy the untouched nature. 
*From early December to the middle of April, the road inside the national park up to Onneto (Hokkaido Route 949 Onneto line) is closed for the winter and vehicles cannot travel near the lake. 
*Depending on the weather conditions, roads may close due to snow, so please check weather and traffic information in advance.