Kikuchi Gorge

Kikuchi Gorge cuts four kilometers through dense forest on the eastern edge of Kumamoto Prefecture, where the Kikuchi River begins its 71-kilometer journey to the Ariake Sea. The gorge drops 300 meters in elevation over that short distance, creating a range of forest types from cold-weather fir and oak at the top to broadleaf evergreens below. The dramatic waterfalls and sheer cliffs result from Mt. Aso's volcanic eruptions 270,000 years ago, which deposited welded tuff that cracks in vertical columns as it cools and then breaks apart under the constant flow of water. The gorge's landscape is still changing as erosion dislodges boulders and reshapes the riverbed.