Akiyoshi-dai Plateau Area秋吉台エリア
The largest limestone karst plateau in Japan, located within a quasi-national park. The most spacious limestone cavern in the entire Orient.
Located within Akiyoshi-dai Quasi-National Park, Akiyoshi-dai is the largest karst plateau in Japan, and is a designated natural monument together with the Akiyoshi-do Cavern.
The karst topography of Akiyoshi-dai was created through a process whereby an area that was a coral reef about 300 million years ago was pushed up to the surface by the displacement of the Earth's plate, turned into a mountain through diastrophism and then eroded by the wind and rain. There you can see limestone in a variety of forms on the green plateau, like the innumerable "karrenfeld" limestone columns, sinks known as "dolines," and a limestone basin called an "uvala," formed by the merging of numerous sinkholes. From the round-shaped Akiyoshi-dai karst observation spot, you can enjoy an extensive 360-degree panoramic view of the area's natural beauty.
The Akiyoshi-do Cavern is the Orient's largest limestone cave, located about 100 meters underground. This huge cave, which took 300,000 long years to be formed into what it is today, was made by limestone dissolving away in the ground water, and it extends for about 10 kilometers overall according to the latest survey. At the present time an about one-kilometer-long section of the cave is open to the public as a sightseeing course, where you can enjoy a variety of fantastic sights, like the Ao-Tenjo (blue ceiling) and a rock formation called the Hyakumai-Zara (100 plates). The temperature inside the cave is always about 17 degrees Celsius, so you need to be sure to wear clothes with long sleeves even in the summertime.
From Tokyo :
[Air] 1h 30 min from Haneda to Yamaguchi Ube Airport, and 30 min from the airport to Shin-Yamaguchi Station by bus, and 40 min from Shin-Yamaguchi Station to the Akiyoshi-do Cavern by bus.
[Rail] 4h 30 min from Tokyo to Shin-Yamaguchi Station by JR Tokaido-Sanyo Shinkansen Line, and 40 min from Shin-Yamaguchi Station to the Akiyoshi-do Cavern by bus.
From Osaka :
[Rail] 2h from Shin-Osaka to Shin-Yamaguchi Station by Shinkansen.