Photo/IllutrationVisitors wearing helmets walk between sheer cliffs enjoying the mysterious view in Aki, Kochi Prefecture, on Oct. 11. (Masatoshi Kasahara)

  • Photo/Illustraion
  • Photo/Illustraion

AKI, Kochi Prefecture--Official visitors to millions-years-old Ioki Cave here have mushroomed from just 229 throughout 2015 to a humongous 6,400 in the first 10 months of 2017.

The actual number of visitors is even higher as not all visitors to the free-to-enter cave are being counted.

People's interest started to grow a few years ago after the Kochi prefectural government began promoting a series of tourist spots in the eastern part of prefecture, which included the relatively unknown cave, affectionately and simply called "Anago" among locals.

Hankyu Travel International Co. began including the cave on tour itineraries in December 2016, and there was even a waiting list last summer.

As well as tour buses, the parking lot near the cave is now often packed with vehicles from outside of Kochi Prefecture on weekends.

“It seems that what attracts people is its magnificent view, the kind that people have not experienced. It is a mysterious and photogenic view,” said an official of Hankyu Travel International.

The cave, through which a stream runs, is located in the city of Aki’s Ioki district. Measuring about 40 meters in length, 3 meters in width and 5 meters in height, it began to be formed about 3 million years ago while a geological layer on the seabed of Tosa Bay rose when earthquakes occurred over and over again and was later eroded by waves.

About 40 species of fern grow in the vicinity of the cave, and it is so rare for so many to exist in the same location that the cluster is designated as a national natural treasure, according to the Aki city tourist association.

After walking through the cave and emerging through the other side, visitors can see sheer cliffs and dense forest with sunshine filtering through foliage, and also hear the sound of the wind that moves the trees. The sunsets are also spectacular in the region.

Fifteen volunteer sightseeing guides work on the tour that includes the cave, and the tourist association is expected to increase the number.

Visitors have been traveling down mainly from Tokyo, Nagoya and Fukuoka on buses hired by leading travel companies. They wear helmets to protect themselves from possible falling rocks and take photos with their cameras and smartphones while guides explain details.

“Now, many people head for the east part of the prefecture including Monet’s Garden Marmottan and the Muroto UNESCO Global Geopark. We want to make them (and the cave) enjoyable tourists’ spots throughout the year,” said Shogo Kondo of the tourist association.