Found near the summit of Mount Hachimantai in northern Honshū, an area rich in volcanic ecology, an otherworldly optical illusion appears for a short time every spring. During this time melting snow and shifting ice combine to create a striking circular pattern that resembles a giant eye staring up from the landscape.
What is the Dragon Eye phenomenon?
The lake most closely associated with the Dragon Eye phenomenon is Kagami Numa, a small volcanic crater lake within Hachimantai National Park in the Tohoku region of northern Japan.
At more than 1,500 metres above sea level, the mountainous area experiences long, harsh winters and the terrain is covered in deep snow for much of the year. When spring finally arrives, the landscape begins to thaw and the melting snow and floating ice sheets break apart and drift into a rough circular formation at the centre of the lake.
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From above, this creates the illusion of a large iris-like ring surrounding a dark centre, which is said to resemble a giant 'Dragon Eye.' The effect is fleeting, often lasting only a few weeks between late May and early June, depending on temperature and snowfall, but the resemblance to a living eye can be uncanny with the surrounding landscape of volcanic ridges, alpine vegetation and lingering snow patches adding to the otherworldly atmosphere.
Why does the eye appear?
Although it may appear mystical, the Dragon Eye is entirely the result of natural physical processes, with the combination of temperature gradients, wind patterns and the lake’s circular basin shape all influencing how the ice melts and moves. As sunlight warms the surface unevenly, sections of ice become buoyant and drift, while remaining snow clings to the outer edges. Over time, this creates a near-perfect ring formation.
The surrounding region of Mount Hachimantai is part of a volcanic plateau formed by ancient eruptions, which has left behind a landscape dotted with marshes, hot springs and crater lakes. This geothermal activity also contributes to the area’s dynamic seasonal changes, with steaming vents and mineral-rich waters shaping local ecosystems.
What wildlife can I see?
Hachimantai National Park is a haven for wildlife, with forests, alpine meadows and wetlands attracting a variety of species, from large mammals to rare birds. The elusive Asiatic black bear is found in the park's mountainous regions, while the Japanese serow, a goat-antelope only found in Japan, is often seen navigating wooded slopes.
Birds of prey, including golden eagles and mountain hawk-eagles can be spotted soaring overhead, while amphibians such as the forest green tree frog and the prehistoric-looking Japanese black salamander thrive in the damp forest undergrowth and rivers.
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