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🇯🇵The Madarajima Stone Potholes, created by 7,000 years of waves, are located in Nagasaki.,JAPAN local trip

SUWANOSEJIMA

🇯🇵 Int'l Island Manga Artist, Ira
🇸🇬 Singapore PR
🌏 ADHD + ASD | IQ 115 | BMI 17.7
⛴️ Fastest to 500 islands in 3 years (World Record)
🙇 Japanese-to-English Google Translation. Apologies for any errors.

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About the potholes on Madarashima Island in Nagasaki

Despite being the largest in Japan, the Jade Stones are little known even to Japanese people.
The Jade Stones can only be seen moving during rough waves. At times like these, it is too dangerous for people to approach the area, making them extremely difficult to observe.

This hole appeared in a crack in a bench of hard, black lava (basalt).
It is 3m deep and 2m in diameter. The hole has a diameter of about 1m at the bottom and contains a boulder about 50cm in diameter.
Locals nickname it “Gyokuseki-sama” (Likely Jade Stone).
In fact, it is the largest of its kind in Japan, but it is virtually unknown in many prefectures.
It was designated a cultural property and a natural monument in 1958.

The waves are very close by, so it’s dangerous to come out here in bad weather.

Lack of signs and difficult to find

First, walk to the white torii gate (you cannot get close by car).
Next, go down the path behind the torii gate to the sea.

I went there during the day. There are arrows painted on the rocks in the area, but they aren’t landmarks and it’s not easy to find.
It’s not surprising that some people give up in this location.
It seems easier to find than the boulders on Terashima Island, which is also in the Hirado Islands.
And if you accidentally drop your cell phone or camera in this hole, it will be impossible to retrieve without a special magic hand.
It’s a windy area. It’s near the sea. Don’t push yourself in strong winds.

Image source 文化庁(2025/9/22付 斑島玉石甌穴 LINK)

Top Page for Inhabited Islands of the Hirado Islands

Ira(アイラ): World record holder for exploring over 500 islands in just about 3 years.
As an island manga artist, Ira serves as a valuable social example of leveraging ADHD and ASD traits to their fullest.
Author of the international island manga MAHARAJIMA(まはらじま).
Holds Singapore Permanent Residency (PR) and a Master’s degree in Intellectual Property.
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6.

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