目白洞

Mejiro-do - Mejirodô Cave - Mejiro Cave


Useful Information

Location: 3-1-1 Horadai, Kokura-minamiku, Kitakyushu-city, Fukuoka-prefecture.
20 minutes by taxi from JR Ishiharamachi Station.
(33.761689, 130.907008)
Open: All year daily 10-17.
In low season on weekdays make a reservation to make sure the reception is manned.
[2022]
Fee: Adults JPY 500, Children (6-11) JPY 250.
Cave Trekking:
Beginners: Adults JPY 3,000.
Advanced: Adults JPY 7,000.
[2022]
Classification: SpeleologyKarst cave
Light: LightIncandescent Electric Light System
Dimension: L=2.1 km, VR=85 m, T=14-15 °C.
Guided tours: self guided.
Cave Trekking:
Beginners: D=2 h, Min=5, Max=10.
Advanced: D=6 h, Min=2, Max=5.
Photography: allowed
Accessibility: no
Bibliography:
Address: Mejiro Cave, 3-1-1 Horadai, Kokura-minamiku, Kitakyushu-city, Fukuoka-prefecture, Tel: +81-093-451-6315.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.

History

AUG-1968 discovered by the Tokyo Gakushuin University Expedition.
AUG-1969 explored by the Shikoku Matsuyama Commercial University Expedition.

Description

目白洞 (Mejiro Cave) is known for having the biggest underground waterfall of Japan, which is 20 m high. The show cave is located in the dry and fossil uppermost level of the cave. The cave was discovered in 1968 by a group of cavers from the Tokyo Gakushuin University. This university is located in a residential district of Toshima, Tokyo which is called Mejiro, near the Mejiro subway station of Yamanote Line. The discoverers named the new cave after this place.

Quite spectacular is a passage where the ceiling is formed by a single layer of limestone. They call it 一枚岩の天井 (ichimaiiwa no tenjō, monolithic ceiling) which is a name, not a scientific term. The layer is stable enough to span a rather wide passage, so the ceiling is almost planar, it looks more like an artificial ceiling built of concrete. Such structures are found in many caves of the world, and while not abundant, they are nevertheless common. But in Japan the situation is different. Normally limestones in Japan are reef limestones which have no layers, or if they have layers, they are deformed by tectonic forces like uplift and folding. In the case of the Hiraodai karst area, limestone is actually marble, the metamorphite of limestone, and during the process of metamorphism internal structures like layers are normally destroyed. As a result this huge and spectacular layer is quite exceptional. This is one of only two show caves in Japan, where visitors can see this, the other is Washizawa Fuketsu in Shizuoka Prefecture.

Quite spectacular is a 20 m high waterfall in a huge chamber or shaft. But this waterfall is not part of the show cave tour, it can only be reached by cave trekking. There are cave trekking tours offered for beginners and sophisticated cavers in the cave, but this tour is definitely the most difficult one. To reach it you must go down, follow the partly water filled river passage, and avoid sumps by using higher dry passages which are often quite narrow. But you can see pictures of the huge shaft-like chamber with the waterfall, which are quite impressive. The waterfall does not flow all year, its best seen after heavy rains or during the wet season.

In front of the cave entrance, beneath the ticket office is a huge tire with the name of the cave written on its side. The tire made by Goodyear is intended for large machines, trucks used in quarries and mines, and has a diameter of 3.7 m. Nearby is a huge limestone quarry, where the limestone is quarried for producing cement and other purposes, right outside the border of the Nature Park. They do not explain why the used this exhibit, but it's a good reminder for the threats which karst faces in a country with such small amounts of limestone.