There was a coral reef here at Akiyoshidai at the bottom of the sea 300 million years ago. Only the limestone remained after the sea receded, and over time the wind and rain carved the rock into dramatic spires and rocky protrusions. The plateau, near the city of Mine in Yamaguchi Prefecture, is unlike anything else you will see in Japan.
However, before you explore the winding trails that run through this rocky grassland plateau, you may want to begin with Akiyoshido, the limestone caverns under Akiyoshidai that form the largest such subterranean system in the country.
Akiyoshido and Akiyoshidai are accessible via an extensive bus network from Yamaguchi City, and also from other cities throughout the prefecture.
Bocho Buses run from Shin-Yamaguchi Station to Akiyoshido Bus Center. From JR Yamaguchi Station, Chugoku JR buses also run to Akiyoshido Bus Center. Two Bocho buses per day run to Akiyoshidai then on to Akiyoshido from Higashi-Hagi Station.
This is where you should start your adventure. Walk through the trees and cross the bridge over the river into the cave known as Akiyoshido.
The cave is large, with a well-maintained path. Gentle lighting preserves the atmosphere of this incredible place, and illuminates the stunning limestone pools, stalactites and stalagmites to great effect. The water running through the cave makes this an aural experience as well as it whittles the limestone into ever-more fantastic shapes.
These caves are Japan's largest, with nine kilometers total. However, only around one kilometer is open to the public.
There are two very famous places inside the cavern. The first is the "100 plates," a huge terrace of limestone that looks like an enormous stack of plates, all washed and ready to serve customers in an underground delicatessen. The other is a gigantic stalactite called the "Golden Pillar," more than 15 meters tall and 4 meters in diameter.
There's a special trail you can climb up for an additional 300 yen that takes you higher up for a great view down into the cavern.
Toward the end of the cave is an elevator that will take you up to Akiyoshidai. The plateau is a five-minute walk up a gentle hill from the exit. When you step out onto the grassland, you'll have a breathtaking view of the karst.
Pampas grass was once grown here for thatch and other domestic uses. The annual controlled burning of the plateau grass has prevented any large trees from growing here. Explore the hiking trails of this extraordinary landscape. The contrast of colors—vivid green, rocky white and sky blue—will light your imagination.
The appearance of Akiyoshi-dai changes naturally with the seasons, and once a year with human intervention.
On the third Sunday in February, Akiyoshidai is set alight in a controlled fire to rejuvenate the grasslands. This event is called Akiyoshidai Yaki. Volunteers set fire to the grasses, and the fire spreads out over the landscape, turning everything black and exposing the rocks.
For anyone who loves natural phenomena, Akiyoshidai and Akiyoshido are perfect for a day trip from Yamaguchi or Hagi.