Yuuka August 22, 2019 Autumn, Photo Spots, Spring, Summer, Winter, Outdoors Onneto: Beautiful Hidden Lake in Hokkaido Yuuka August 22, 2019 Autumn, Photo Spots, Spring, Summer, Winter, Outdoors This 2.5 km-around beautiful lake is in the Akan-Mashu National Park. Once you get there, you will be greeted with the amazing colors of the lake and its natural surroundings.