When traveling in Yamaguchi Prefecture one of the places that you should definitely try visiting is Mine City, home to Akiyoshido Cave, the largest and longest limestone cave not only in Japan but in Asia as well. The cave, which contains five and a half miles of passage ways and is 328 feet wide was named by Emperor Hirohito in 1926 when he was still the crown prince. Today, visitors can enter a section a little over half a mile long, which has been designated as a public sightseeing course.
The cave is part of the Akiyoshidai Plateau, an area dotted with limestone pinnacles. The plateau is believed to be a 300 million year old coral reef, which in time was eroded by rain. Both the cave and the plateau are designated as a quasi-national park.
Akiyoshido Cave is relatively easy to navigate as there are paved pathways and ample lighting. The temperature inside the cave is a constant 63°F throughout the year making for a comfortable environment. Once inside, visitors will be treated to breathtaking limestone terrace pools filled with water, stalactites, which form natural sculptures and underground waterfalls. For an additional ¥300, they can traverse an adventure path, which is slightly difficult to navigate but offers a splendid view of the cave from a higher vantage point. The cave is home to six types of cave bats including the miniopterus fuliginosus also known as the Eastern Bent-Winged Bat which measures between 4-5 inches in length.
There are three entrances to the cave system: Akiyoshido Visitor Center (Akiyoshido front entrance), Kurotani Visitor Center (Kurotani) and Akiyoshidai Visitor Center (via elevator). The Akiyoshido entrance is the closest to the bus terminal and main parking lots while the Kurotani entrance is often utilized by tour groups. From the elevator entrance, it is a 5-10 minute walk to an observation deck. Visitors can glimpse nice views of the Akiyoshidai Plateau from this pathway. There are buses which run between the cave’s three entrances. They run relatively frequently on weekends and holidays but are often infrequent during weekdays.
The cave is open year round between the hours of 8:30 AM and 4:30 PM. Getting to the cave is straightforward using buses, which depart from both Yamaguchi Station and the Shin-Yamaguchi Shinkansen Station and drop passengers off at the cave entrance. There are also buses departing from Shimonoseki. The journey from these stations to the cave usually takes one hour so plan accordingly.