Lake Toyoni is a 30-hectare lake about 9 kilometers up the forest road along the Saruru River on the north-eastern slope of Mt. Toyoni. This is the only natural lake in the Hidaka Mountain area. From its heart shape, it is called “Lake Heart.” It is also known as “Lake Batei (horseshoe)” because it also looks like a horseshoe. The Ainu people called it “Kamuito,” meaning “God Pond.”

The quiet lake full of emerald green water is surrounded by thick primeval forests, where northern pikas and Ezo squirrels inhabit. If you are lucky, you may get a glimpse of one. With only the twittering of birds, the lake lies in total tranquility. From early to the middle of October, it is surrounded with wonderful autumn leaves. It is the most suitable scenic spot for those who favor quiet natural environment.