Towards the southern end of Akiyoshidai is the  Akiyoshidō cave, named by Emperor Hirohito on May 30, 1926, when he was still crown prince. This spacious cave is up to 100 meters wide and has 8.79 kilometers of passages, making it one of the longest in Japan after Akkadō cave, and one of the longest in Asia.
Akiyoshidō cave, named by Emperor Hirohito on May 30, 1926, when he was still crown prince, is a spacious cave located at the southern end of Akiyoshidai. This extensive cave has passages that extend up to 8.79 kilometers in length, making it one of the longest in Japan after Akkadō cave and among the longest in Asia.