Akiyoshidō
Interesting facts
- Japan's first ever cave dive took place here in March 1962, when two divers explored Koto-ga-fuchi, the deep pool at the inner end of the show section.
- When the cave was renamed in 1926, the telegram carried only the reading Akiyoshidō, so officials first guessed the wrong characters until a reply confirmed the 'yoshi' meant 'fragrant'.
- The 25-year-old crown prince who inspired the new name spent about an hour underground in 1926, overrunning his planned schedule by some 40 minutes.
- Six named features inside were renamed along with the cave; the famous rimstone terraces of Hyakumai-zara had earlier been called Chijimi-zara.
- In the 1840s men from the medical school at Hagi entered the cave to break off stalactites, which were then valued as a medicinal ingredient.
- Deep inside, the air stays at about 16 °C and 95% humidity all year, while near the huge mouth temperatures swing between roughly 5 and 18 °C.
- Ash from an eruption of the Aso caldera on Kyushu, some 80,000 to 90,000 years ago, blanketed the plateau above and was washed down into the cave.
- Koto-ga-fuchi, the cave's largest underground lake, is about 60 metres long, 15 metres wide and 3 metres deep.
- The cave shelters endemic tiny creatures such as the springtail Sinella akiyoshiana, while mosses and ferns have sprouted under its electric lights.
- Around 1904 Edward Gauntlett donated a boat to ferry people along the underground river; it stayed in use until a walkway replaced it in the early 1950s.
Why it is worth it
Akiyoshidō is the largest limestone cave in Japan open to visitors, a river cave hollowed out 100 to 200 metres beneath the Akiyoshidai karst plateau in Yamaguchi Prefecture. An underground stream runs for roughly a kilometre from the inner pool called Koto-ga-fuchi to the great mouth of the cave, and the visitor path follows it upstream through a sequence of chambers. Cave divers working from the 1990s onward linked the system to other passages several kilometres to the east, and surveys begun in 2016 pushed its total mapped length past 10 km.
The named sights read like a catalogue of cave forms. Hyakumai-zara, the "hundred plates", is a cascade of rimstone pools stepping down the slope like terraced paddies. Senjōjiki is a single hall about 175 metres long, 80 metres wide and 35 metres high, with the path climbing over a vast pile of collapsed rock. Kōgen-bashira, the "golden pillar", is a towering column of flowstone treated as the cave's emblem, and Dōnai-Fuji is a five-metre stone column that spreads at its base like the slopes of Mount Fuji. Near the entrance the cave breathes with the seasons: in summer cold air from the depths meets warm air from outside and often fills the passage with mist, while in winter a column of vapour rises from a 90-metre shaft that reaches the surface.
Local tradition credits a Zen monk with rain-making rites inside the cave during a great drought in 1354. For centuries it was known simply as Takiana, the "waterfall hole". It was explored in 1907–1908 by Edward Gauntlett and the geographer Nakame Satoru and opened for visitors in 1909. In 1926 the then Crown Prince, later Emperor Shōwa, toured it, and after his visit the cave received its present name, Akiyoshidō. It was designated a Natural Monument in 1922 and a Special Natural Monument in 1952, and in 2005 its underground water system was listed under the Ramsar Convention.
Getting there
The cave lies in the eastern part of the city of Mine, Yamaguchi Prefecture, about 9 km from the centre of Mine. The nearest airport is Yamaguchi Ube Airport (UBJ), about 33 km away. Buses run to the Akiyoshidō bus terminal from Shin-Yamaguchi Station on the Sanyō Shinkansen, roughly 17 km to the south in a straight line, and the Akiyoshidai interchange of the Ogōri–Hagi road is a few minutes' drive away.
On these lists
34.22811, 131.30347per Wikidata