Misty Lake Mashu Caldera & Kaminoko-ike Spring Pond

Category: Crystal Caldera Lake & Natural Mist Wonder | Location: Teshikaga-cho, Kawakami-gun, Eastern Hokkaido 088-3200

Nestled in Akan-Mashu National Park in Eastern Hokkaido, Lake Mashu (*Mashu-ko*) is internationally celebrated among limnologists as one of the purest, most transparent volcanic bodies of water on Earth. In 1931, scientists recorded an astonishing water clarity visibility depth of 41.6 meters, rivaling Russia’s Lake Baikal. Indigenous Ainu people venerated the caldera basin as *Kamuinupuri* ("Mountain of the Gods"), considering the untouched lake a sacred sanctuary belonging strictly to celestial deities. Enclosed by sheer, nearly perpendicular volcanic crater ramparts rising 300 to 400 meters above the water surface across a 20-kilometer perimeter, Lake Mashu is completely landlocked, fed solely by pure rainwater and snowmelt without any inflowing or outflowing river channels. In the absence of organic sediment runoff, the 211-meter-deep waters reflect an incomparable, intense sapphire-indigo hue globally termed "Mashu Blue." Yet more often than not, the lake is enveloped by sudden blankets of dense swirling fog (*Kiri no Mashu-ko*), giving rise to romantic folklore that visitors who see the clear water on their first attempt will experience delays in marriage or career. Because the lake shoreline is strictly protected with public access completely prohibited to maintain ecological purity, visitors gaze down from three spectacular rim-top viewpoints: Observatory No. 1, offering modern visitor amenities and Mashu-blue soft-serve ice cream; Observatory No. 3, perched on an airy crag with breathtaking angles over the tiny volcanic island Kamuishu at the lake’s center; and Uramashu Observatory on the quiet northern rim. Nearby across the outer caldera ridge lies Kaminoko-ike ("Child of the Gods Pond"), a surreal 5-meter-deep turquoise spring pool fed by subterranean seepage from Lake Mashu where centuries-old fallen spruce trees lie perfectly preserved without decaying. Lake Mashu is a 15-minute drive from JR Mashu Station.