Sea & Nature

Akiyoshidai Karst Plain and Akiyoshido Cave - 350 million years of Geological History

Akiyoshidai Karst Plain and Akiyoshido Cave - 350 million years of Geological History

Having got lost more times than I care to recount, arriving at the Akiyoshidai Karst plain in Yamaguchi Prefecture’s Mine City was more challenging than I’d expected, but then again, navigation isn’t really more forte. Still I managed to locate the plain and decided to park at the bottom for an energetic releasing walk up the hill as a release from being car bound for hours. After bit of a hike I was welcomed by the sight of rolling hills, peppered with white limestone.


Rolling plains filled with Karst stone present an unusual site.


Up close you can imagine the karst rock as they once existed as coral on the sea bed.


The coffee at Karstar provided a much needed caffeine boost.


The town level entrance to Akiyoshido Cave.


The content in the cave is varied and stunning.


The delicate interplay between colors and shading present a fascinating site.


The terraced limestone pools filled with water are captivating.

Allowing myself a moment to stop, breathe in the fresh air, and gaze out over the fields of green, I could relax my shoulders and expunge some of the car-seat kinks from my legs and arms.

The Akiyoshidai plateau is a quasi-national park of some 4,502 hectares. Yes, it is huge. I was fascinated with the sight before me, such a contrast to the green-filled hills I had been driving through all day. In fact, the whole area looked like it had been transplanted from a completely different country, or even planet.

From where I was standing at the visitor center it seemed as if these open hills rolled out endlessly. A magnificent site. After running around for a few minutes trying to catch some nice light before I lost the battle with the diminishing afternoon sun, I decided to seek out some extra information.

The bubbly staff gave me an enthusiastic greeting, handing over piles of information, both in English and Japanese. I was also excited when I turned to see a cafe with an espresso machine, the perfect place to take in all this new information, and get a much needed caffeine boost. Ended up the café makes a very nice fresh ground coffee. I was impressed.

Recharged, I bolted up the stairs of the viewing platform for an even higher vantage point to admire the scenery and was not disappointed. Next thing on my agenda, I wanted to get a close-up look at these fascinating stones.

So, I walked out into the fields filled with green to examine what, 350 million years ago, had once lay at the bottom of the sea as banks of coral reefs. The white of the limestone really creates a striking contrast with the surrounding green plants, in some places standing as high as my shoulders.

A little pressed for time I dragged myself away from the plain, and on to my next destination. I was racing the clock because the massive cave below the mountain would close for the day, so, this time I asked directions and jumped in the car to park down at the bottom of the mountain. Actually, there was an elevator option if you want to descend straight down into the cavernous space from above, but it closes earlier than the town level entrance, so I went for the latter option to make the most of my available time in the underworld.

After strolling through town, I buy my ticket from a chatty ticket seller who tells me that if I have my passport I can get a 500 yen discount. Luckily, I have the navy-colored ID book handy and saved enough for a cheap bowl of ramen that had earlier caught my eye.

Approaching the cave, I didn’t quite know what to expect, but the water gushing into the river at the entrance was crystal clear, giving a strong indication that something special awaited me.

A single, huge fish played in the strong current, prompting me to wonder what life I will find inside. Bats I guessed, as I made my way into a huge cavern, alone. I was not prepared to be as affected as I was, but it felt like embarking on a journey back through time into this wondrous subterranean world. Like a history lesson, the rock formations were revealing the secrets of past ages folded in on themselves beneath the very physical presence of newer eras and environments.

Here, shades of light eclipse colors, creating a subtle spectacle, an eeriness compounded by the sound of intermingling water, and this watery symphony was the accompanying music for every step I took. As the rock ceiling seems to climb ever higher, the lamps intermittently lining the elevated walkway seem to shrink doubly quick as they disappear into the distance and around corners, either suddenly or gradually disappearing into darkness.

Halfway along the path – although I wasn’t aware when I first passed through – the water becomes still, perhaps deep enough to continue flowing far below. This still pond forms a perfect glassy mirror reflecting the high orange rock wall nearby.

Just a few steps further and limestone seems to cascade down in pools of stillness resembling terraced baths of white stone. I stop to stare, alone in the dark. It seems quite a special moment to be able to have the time and freedom to pause and contemplate nature deep inside the Earth. But all I can fathom now, is the beauty of the curves and colors.

I continue to the end before turning back, noting names given to various scenes and rock formations, though it all seems somehow irrelevant next to soaking in the ambience of geological history. On my return journey I strained my eyes for some bats, but alas was disappointed.

Stepping out from the dark tones normally hidden under earth and soil, the autumn colors seemed brighter and the world larger, the air seemed sweeter than ever. The world outside felt somehow different after my 40 minute adventure through 300 million years and back again.

Photographs by Julian Littler & Mine City Text by Julian Littler



Yamaguchi is surrounded by ocean, mountains and rivers and is characterized by its climate, which is comfortable throughout the year. Its natural scenery, which includes some 1,500 kilometers of coastline, is a cut above. The prefecture has Kintaikyo Bridge, one of the three most famous bridges in Japan, and other tourist attractions, and its fugu (pufferfish) is famous as a winter dish.