A caldera lake with a maximum depth of 211.4 meters located in the eastern part of Hokkaido. Having no inlets or outlets, Lake Mashu is known as one of the clearest lakes in the world. Surrounded by steep crater walls, the lake enchants visitors with its distinctive blue surface reflecting the sky known as “Mashu Blue.” Because of its mystical beauty, it is also called the “Lake of the Gods.” However, being able to see this breathtaking view is extremely rare, as the lake is usually covered with fog. There are myths connected to the lake that if an unmarried woman sees Lake Mashu without fog, she will marry later in her life and that if a man sees it on a clear day, his promotion will be delayed. Ken, a visitor from Tokyo, was relieved to miss the awestriking view, as his promotion exam was just a few weeks away.