It is the largest and deepest lake in the Kirishima Volcano Group, with a diameter of about 1 km, spanning the cities of Miyakonojo and Takaharu.

It was formed by a phreatomagmatic eruption about 4,600 years ago. The eruption was the largest known eruption of the Kirishima Volcanoes, and the surrounding crater walls form a steep cliff about 30 meters high. It is a superb spot where you can see Takachiho Peak behind Futagoishi. There are facilities such as a small pond, Miike Shrine, and a wild bird forest in the vicinity, and it has become a base for outdoor activities.
You can also see a beautiful view of Miike from Kirishima Higashi Shrine in the neighboring Takahara town.

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