日本三大秘境のまち

Due to its central location, Tokushima’s Miyoshi City is often called the “naval of Shikoku”, and perhaps the naval of Miyoshi would be the Yoshino River, which flows right through its center. Within here the river forms the spectacular Oboke Gorge, and a great way to interact with and learn about this natural wonder is through a Geo-Tour offered in collaboration with the Miyoshi Geo-Guide Association, the Yamashiro Sengoku Kunizakai Group, and Obokekyo Mannaka Pleasure Boats.

Oboke Gorge Pleasure Boats

After the 45 minute interactive lecture, we walked down the pathway behind Obokekyo Mannaka Service Area to take a boat tour upon the Yoshino River.

These boat tours have been in operation through Oboke Gorge for over a hundred years, but nowadays the boats are modernly outfitted with comfortable seats, retractable roofs for when there is bad weather, and of course, special safety equipment.

Oboke Gorge: A National Natural Monument

The weather on the day of the tour was a bit bad, but it didn’t affect the lovely emerald waters of the Yoshino River, which was so clear that you could see the bottom where it was shallow.

Looking up, the steep rocky slopes rose almost vertically, and due to the rain they glistened in hues of blue and grey.

The name “Oboke” is a bit unique, and it best translates as “Big Step Danger” with many people nowadays claiming this name is derived from how taking a big step in this perilous, cliff-filled place would be quite dangerous.

However, during the presentation, the Geo-Guides explained how the original name (which has the same pronunciation but with a different meaning) actually meant “steep cliff”.

But whatever the “real” name may be, the gorge here was definitely full of steep cliffs, and without the well maintained paths leading down, it would certainly be a rather dangerous place to walk.

Seeing the Strata of the Earth

As we rode through the gorge on the boat, the guides explained how the exposed rock layers we were seeing were formed about 200 million years ago, back when dinosaurs roamed the earth. 

Then, about 3 million years ago, the central section of the gorge began to rise, such that we passed right through the specific area of rock which was being pushed up the highest, and on either side of this up and down river the rocks layers were angled upward towards the center.

As we continued through the narrow gorge, the geological forces along with the power of the river water had shaped the surround rocks into some rather impressive formations, with some of them taking shapes that even looked like animals. 

Signs of Life

Even though it was mid-February, we were treated to a hint of the coming spring in seeing a few early blooming rhododendrons, with their bright pink flowers contrasting sharply off the harsh blue-grey rocks.

There were also several birds moving about, including some ducks that swam past us in the river.

Indeed, even though the mid-winter views around us seems bleak and harsh, the power of nature made itself known in a wide variety of ways.

For sure, to look down from above into Oboke Gorge is certainly beautiful, but to look up at these hanging cliffs from a boat upon the Yoshino River is perhaps even more impressive.

In Part 3 we’ll speak some more with the guides from the tour organizations. 

For more about the Miyoshi Geopark Project, check their Facebook page:

https://www.facebook.com/people/みよしジオガイドの会/100057168981171/

And info about the Yamashiro Sengoku Kunizakai group is available on their Instagram page: 

https://www.instagram.com/sengoku_kunizakai/

And for info about Obokekyo Mannaka Service Area and their Pleasure Boat tours, check their website:

https://www.mannaka.co.jp/restaurant/excursionship/excursionship.html 

(Text & Photos by: Shaun Lamzy)