Tensodo Cave

Dogashima Tensodo, which has long been a popular scenic spot on the west coast of the Izu Peninsula, is a sea-eroded cave known for its appearance as if it has a hole in its roof called a skylight.

Inside the cave, light shining through the skylight illuminates the emerald green surface of the water and walls, creating a mysterious scene.

The area including Tenmado-do Cave has a beautiful coastline facing Suruga Bay and is designated as a national scenic beauty spot as “Izu Seinan Kaigan” (southwest coast of Izu).

The geology of Dogashima is composed of quartz andesite tuff called the Shirahama Formation of the Neogene Miocene age.

Because this tuff is susceptible to wave erosion, numerous sea-eroded caves have formed in the surrounding area, creating a unique topography.

Tenmado Cave, which is made of white tuff, is a sea cave formed by wave erosion.

The interior of the cave has a complex honeycomb-like structure and can be entered from three different entrances.

The south and west entrances open toward the sea, while the east entrance opens toward the mountain side. The cave is connected by two side holes, and the total length of the cave is 395 meters.

Visitors can enter the cave through the south entrance, which is particularly wide and 147 meters long. The shape of the cave resembles the character for “well,” creating a magnificent landscape.

Then, when you proceed to the center of the cave, you will find a skylight with a rounded ceiling that has fallen away. This hole, with a diameter of more than 10 meters, was created by multiple sinkings and collapses.

A band of sunlight shining into the dark cave illuminates the emerald surface of the sea, creating a mysterious sight.

The poets Tekkan Yosano and Akiko Yosano visited this place and composed poems about its beauty.

There is a window in the back of the island’s cave, and the shimmering tide throws the color of a peacock onto my boat.
Tekkan Yosano

“Is it the spring rain that glints off the skylight of Dogashima Tenso-do?
Akiko Yosano

Tenmado-do Cave is located on the Dogashima promenade course and can be viewed from above, and a sightseeing boat ride is also available to tour the cave.

The “Dogashima Cave Tour Boat” offers a scenic tour of the islands around Dogashima, the natural monument Tenmado-do Cave, and other oddly shaped rocks along the beautiful coastline.

The boat provides explanations of the islands and a variety of sightseeing courses, allowing visitors to fully enjoy the tour even in a short time.

Nishi Izu Town is known for its beautiful sunsets, and Dogashima Island also offers a fascinating sunset spectacle.