Mysterious Lake Mashu is one of the world's clearest, most transparent lakes. The lake was catapulted to fame in the 1960s with the hit song, “The Mists of Lake Mashu,” and in 2001, was designated as a “Hokkaido Heritage” site.


LAKE OF THE GODS
Lake Mashu is a caldera lake lying 315 meters above sea level, born from the fires of a massive volcanic eruption nearly 7,000 years ago, and dominated by Akan-dake (elevation 858 meters), known as “The Mountain of the Gods” to the Ainu people, at the lake's south eastern edge. Slightly larger than Lake Akan, Lake Mashu has a circumference of 20 kilometers, covers an area of 1,966 km2, and has a depth of 212 meters. With no incoming or outgoing river currents, the lake has a deeply serene, mirror-like surface and is surrounded by 300-400 meter high sheer cliffs. The lake is known for the mist and fog that often forms here, and as its name in the Ainu language, “Kamuy-tou” (“Lake of the Gods”), implies, it presents a stately and mysterious atmosphere.


AND THE WORLD RECORD FOR TRANSPERANCY GOES TO ...?
A 1931 transparency survey of Lake Mashu recorded an underwater visibility of 41.6 meters, exceeding that of Lake Baikal in Russia, and confirmed the establishment of a new world record at the time. However, with the later introduction of sockeye salmon and rainbow trout into the lake, the transparency has shown a decreasing trend year after year. At the same time, a transparency survey has not been carried out on Lake Baikal in over 70 years, and with increasing development in the surrounding area, underwater visibility is thought to have significantly decreased. As the record is an old one, the truth is that no one really knows which lake is the world's clearest, but there is no doubt that Lake Mashu is at least one of the world's clearest, most transparent lakes.


THE LAKE MASHU DIMPLE
The tiny island of Kamyush lies at the center of Lake Mashu. This small spit of land is also known as the “dimple” of the lake, and its name in the Ainu language means, “the old woman who became a god.” This island rises as much as 30 meters from the lake surface, but in actuality it is part of the volcanic summit projecting its face from the water at an elevation of 240 meters.

THE JINX OF LAKE MASHU
Often enveloped in dense fog and mist, Lake Mashu has an image of being “always covered in fog, and only sunny once in a blue moon.” Because of this, it's said that those who see the lake when it's sunny and without fog will either not be able to marry until later in life, break up with a loved one if with that person at the time, or be unable to advance their career, and therefore jinxed!


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