Okayama Niimi City

The Seto Inland Sea Inside Ikura-do, a 1.2km Long Limestone Cave?!


The Ikura ravine was formed as a result of the Takahashi River eroding through the karst plateau.

While Ikura Falls descends from a height of around 70 meters from the steep precipitous cliffs, hidden beyond there is a large limestone cave called Ikura-do Cave!



Crossing the pedestrian bridge over the river, I reach the cave’s entrance, which marks the start of my exploration of this unusual space that has a total length of 1.2km!

As soon as you enter, cool air from deep within the cave hits you. Truly a natural cooling system, the average temperature within the cave is +-15℃. This kind of coolness feels wonderful during Japanese summer, right?


Created by the accumulation of material contained within dripping water, the cave’s interior has given birth to mysterious works of art such as stalactites that grow from the ceiling like icicles, and stalagmites that grow from the floor.

One of the cave’s highlights, this is called “Ginsudare”.

Stalactites that hang from the high ceiling connect with the stalagmites growing from the floor to form stone pillars.



The cave’s sightseeing route has a height difference – you climb up around 90 meters.


As there are some slightly slippery patches formed by dripping water along the way, be careful as you move forward!



This is the “Chijiku Waterfall”.

The photo above is of the waterfall’s mouth. The total height of the waterfall is 50 meters, the biggest in-cave waterfall in Japan.

To imagine, the Seto Inland Sea within the cave?!

Naturally this is not seawater, but there are several stalagmites floating in the spring filled to the brim with underground water, which makes it look like the Seto Inland Sea dotted with islands, and that’s why it was named “Seto no Umi” (‘Sea of Seto).

These mysterious creations of nature just make you raise your voice in astonishment!



These stalactites are called “Chikurin” (‘Bamboo forest’).


Overwhelming everyone who sees them, mysterious and beautiful stalactites appear before you one after another along the sightseeing course!

There are plenty of other highlights such as the “Kurageiwa” stone and “Mizugoromo” as well.



Finally we see the exit!

The Ikura-do cave sightseeing course runs for a total of 1.2km, and in western Japan it’s second only to Akiyoshi-do cave located in Yamaguchi prefecture.

You need about 40 minutes to complete the tour, but if you wish to take a good look at each of the sights, it takes more than 1 hour. (*Midway, there’s also a short cut to the exit.)

The cave interior is a treasure house of natural works of art formed over an astoundingly long period of time. How about coming to Ikura-do cave to check them out??


Ikura-do Cave
Location: 409 Ikura, Niimi city, Okayama prefecture
Guide Homepage: http://www.ikurado.jp/ (Japanese)
Admission: Adults JPY1000, Middle school students JPY800, Children JPY500
Open: 8:30-17:00 (Last entrance at 16:30) *Start of the year (January 1st thru 4th) open 9:00-16:00
Closed: Open all year round

Setouchi Finder Photo-writer: Hironobu Matsuoka


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Written by

Hironobu Matsuoka

Hironobu Matsuoka

Hironobu Matsuoka / Photo-writer Born in 1974 in Nishinomiya, Hyogo Prefecture, and currently living there, Hironobu is the president of Mediapolis Inc. "I travel around the country in Solar King, an eco-camping car that has a solar power generator, and film the beautiful scenery of Japan in high-definition. I want to move around the country as much as possible and leave behind videos of precious Japanese nature and scenery for future generations to enjoy. Although I travel all over the country, I love my home area of Setouchi." 'Healing Japan TV' - Traveling virtually around the country through 'healing videos'.



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