Tamasudare Waterfall is a 63-meter-tall waterfall located in the Dewa Mountains. It faces northwest, and depending on the sun’s position and how the light hits the water, it can sometimes look like a woven screen (sudare), giving the waterfall its name.
About 15 million years ago, the Dewa Mountains were at the bottom of the sea. At that time, volcanoes erupted on the seafloor, and the basaltic lava that flowed out cooled and hardened to form the cliff of Tamasudare Waterfall. If you look closely at the cliff, you can see vertical cracks, called columnar joints. These columnar joints can also be found on Tobishima Island—which was at the bottom of the sea around the same time, also being formed by undersea volcanoes.
About 3 million years ago, movement in the Earth’s crust pushed the Dewa Mountains from east and west, causing them to rise from the sea. As a result, the rocks that were once at the bottom of the sea eventually became this waterfall.
Nearby you can see not only the beautiful natural scenery, but historical and cultural sights as well, including Mitake Shrine, which holds a story about the Buddhist monk and poet Kōbō Daishi (Kūkai).