Kagami-numa (Hachimantai Dragon Eye)

For a few weeks each spring, a small crater lake near the summit of Hachimantai turns into a giant eye staring up at the sky. As the snow melts, the surface of Kagami-numa thaws first around its rim, leaving a pale disc of snow and ice floating at the centre, encircled by a ring of deep blue meltwater. The effect, seen from the path above, is so much like a vast iris and pupil that the lake has become known as the Hachimantai Dragon Eye, a name that won it the Cool Japan Award in 2019.

Kagami-numa, whose name means "mirror pond", sits just below the 1,613-metre summit of Hachimantai, on the border between Iwate and Akita prefectures in the Towada-Hachimantai National Park. It is a crater lake: Hachimantai belongs to the Nasu volcanic belt and was shaped by repeated large eruptions during the Quaternary period, and when activity ended, water gathered in the hollow of a vent. The lake has a circumference of roughly one kilometre and is only about three metres deep at most, cradled in a bowl-shaped depression around 50 metres across.

The phenomenon appears during the snowmelt season, typically between May and June, and depends on the depth of the winter snow, the timing of the thaw and the weather in the days before; its shape changes from day to day as the central disc shrinks and cracks. Outside that brief window the lake is a quiet sheet of water near the top of the Hachimantai plateau, a high volcanic upland in the north of Honshu.

Getting there

Kagami-numa lies a short walk of about ten minutes from the Hachimantai summit parking area, which is reached by the Hachimantai Aspite Line mountain road from the Matsuo-Hachimantai interchange on the Tohoku Expressway. The nearest town is Hanawa in Kazuno, about 26 km away, and the nearest airport is Odate-Noshiro Airport (ONJ), about 49 km away.