Ryusen-do Cave龍泉洞（りゅうせんどう）

The mysterious, raw beauty of underground lakes. Experience the deep, dark beauty of Japan's famous limestone caves here.

Ryusen-do Cave, which can be found in the foothills of Mt. Urera-san at the east of Iwate, is one of the three largest limestone caves in Japan and is listed as a natural monument. The precise length of the cave is not known as nobody has explored its full length - 2500 meters of it has been explored to date. It was confirmed sometime ago that there are many tributary caves inside Ryusen-do Cave, two of which are named Komori-ana (Bats Cave) and Kameiwa-shido (Tortoise Rock Cave). As the name Komori-ana suggests, there are five different species of bats living in Ryusen-do Cave and each species is listed as a natural monument.


Inside the cave, there are a few underground lakes that are filled with spring water which flows into the lakes from the very deep back of the cave. The first three lakes are open to the public, which are approximately 700 meters from the entrance of the cave. The clarity of these lakes is internationally recognized, especially the third lake, the depth of which is 98 meters. It glows emerald green in an artificial light fascinating your eyes with its mysterious beauty.