About a five-minute walk downhill from the parking lot, you will come across Tsūtenkyō Arch, a beautiful landform sculpted by nature. Let’s take a walk down the path.

An explanation signboard sits partway down the hill. Please stop along the way and take a look. The scenery you can see from the signboard’s location is called Tenjōkai, which means “Heavenly World.” It was created over time by the rough waves of the Sea of Japan. Of particular interest is the tall, thin rock called Kannon-iwa. If you visit when the setting sun lines up just right with the rock, it looks like a candle lit on fire, earning it the nickname “Candle Rock.”

As you arrive in front of Tsūtenkyō Arch, first notice its shape. Tsūtenkyō Arch was once a cave, created by waves that slowly ate away at the rocks on the coast. A landslide then caused the back part of the cave to collapse, leaving only the entrance of the former cave standing to form the arch shape you see now.
Next notice the color pattern in the rock, with both red and black portions. Both red and black are made of basalt, a volcanic rock made by lava from repeated eruptions. The difference is that the red rock was oxidized by exposure to air as the lava cooled. In other words, each pair of red and black can be counted as one single eruption of the former volcano. The yellowish-colored rock is trachyte, a different type of rock that was formed by lava that flowed through here later, intruding to form another layer inside the already existing rock formation.

The islets scattered off the coast to the left of Tsūtenkyō Arch can be seen as a later stage of the same process that created the arch. Bridge-like arches underwent more erosion from the sea and wind, and their upper or ceiling portions broke away, turning them into the sea stacks you see now. Tsūtenkyō Arch will also one day collapse and become a sea stack separated from the island. This is what makes the scenery before you so precious.