Акан-Машу көлі: Японның мөлдір суы мен құдайлар тауы

Crater lake in Akan Mashu National Park, Hokkaido island, Japan

Lake Mashū (摩周湖) (Ainu: Kamuy to) is an endorheic crater lake formed in the caldera of a potentially active volcano. It is located in Akan Mashu National Park on the island of Hokkaido, Japan. It has been called the clearest lake in the world.

Lake Mashū is surrounded by steep crater walls high. It has no significant inlets and no outlet. The lake is one of the clearest in the world and one of the deepest in Japan. On August 1, 1931, the transparency of the water was measured at Around the same time Lake Baikal was measured This is the basis for the lake's claim to be the clearest in the world. The loss in transparency is probably due to the introduction of sockeye salmon and rainbow trout into the lake and landslides. At the same time, the clarity of Lake Baikal has not been measured. In summer, the surface of Lake Mashū is often obscured by fog. There is usually fog covering around the lake for about 100 days of the year. This has given the lake a reputation for mysteriousness. This was rendered as Lake Mashin (魔神湖) by the Japanese. Over time, however, the Japanese began to refer to the lake by the Japanese reading for the neighboring peak, Mount Mashū (摩周岳). The kanji for this peak translate roughly as scrubbed area mountain. The Ainu name for this peak, by which it is commonly known today, is Kamuinupuri or mountain of the gods. The lake also retains its Ainu name, Kamuito or lake of the gods.

The Mashu dake Hiking Course is a trail that goes along the crater rim and to the top of Mount Mashū. The trail leads through forest and grassland for about seven kilometers and takes about 2.5 to 3 hours to hike one way. There are no settlements along the shores of the lake. Access to the lakeshore itself is prohibited by the Ministry of the Environment (Japan). Visitors may only view the lake from the designated observation towers.

Sendoff Spring in Pokémon Diamond and Pearl and Pokémon Platinum is based on this lake as the Sinnoh region is a fictionalized version of Hokkaido.