Nagatoro Iwadatami

Nagatoro Iwadatami refers to the rock formations along the Nagatoro Gorge in the Chichibu region of Saitama Prefecture. Formed along the Arakawa River, these rock beds stretch approximately 50 meters wide and 600 meters long. Known as the “Window to the Earth,” the area is famous not only for the rock slabs but also for exposed crystalline schist, allowing visitors to observe the Earth’s geological interior. It is designated as both a National Scenic Spot and a Natural Monument. Nagatoro is also considered the birthplace of Japanese geology and attracts attention nationwide as a fundamental site for geological research. The rock formations belong to the Sanbagawa Metamorphic Belt, and across the river stands a steep cliff known as the Chichibu Red Wall, named for its reddish color caused by oxidized iron. Visitors can also enjoy the Nagatoro Line Descent, a traditional Japanese boat ride down the Arakawa River lasting 30 to 60 minutes, guided by skilled boatmen (service may be suspended during winter, so advance confirmation is recommended). Myojin Falls, located nearby, is a popular power spot among younger visitors. Nagatoro Iwadatami is just a one-minute walk from Nagatoro Station on the Chichibu Railway.