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Towards the southern end of Akiyoshidai is the Akiyoshido cave, named by Emperor Hirohito in 1926 when he was crown prince. This cave is up to 100 m wide and has almost 9 km of passages, making it the longest in Japan and one of the longest in Asia. An approximately 1 km-long section of the cave is open to the public as a sightseeing course, with a walkway and bridge system, entering at the cave's lowest point and exiting by an artificial elevator. This portion of the cave is also well decorated with a variety of large and colorful speleothems. Akiyoshi Cave and the main observatory can be reached on foot, but cars or "karst taxis" are necessary to reach other caves. A one-day taxi pass costs ¥800.

includes the Akiyoshidai (秋吉台, Akiyoshi plateau) and Japan’s longest cave, the Akiyoshido (秋芳洞), the latter of which is designated a Special Natural Monument. Akiyoshidai is served by a natural history museum, visitor center, rest house, youth hostel and park headquarters building, and is traversed by a scenic roadway and several walking trails. Events include a fireworks festival in July, a “Karst Walk” in November, and an annual burning off of dry grasses in February called Yamayaki. Akiyoshidai is a part of the largest karst topography in Japan. The park is best reached by direct bus from Shin-Yamaguchi Station, though there is also service from JR Yamaguchi Station, Hagi, and Shimonoseki.