Ryusen-do

Ryusen Cave - Dragon Spring Cave


Useful Information

Location: Iwaizumi-tyo. From Morioka National Route 455. From Hanamaki Airport National Route 4, then National Route 455.
Open: OCT to APR daily 8:30-17.
MAY to SEP daily 8:30-18.
[2020]
Fee: Adults JPY 1,100, High School JPY 1,100, Junior High School and Elemetary School JPY 550, Children (0-5) free.
Groups (15+): Adults JPY 930, High School JPY 770, Junior High School and Elemetary School JPY 380.
[2020]
Classification: SpeleologyKarst cave
Light: LED.
Dimension: L=4,088m, T=10°C.
Guided tours: L=700m, D=30min, ST=270.
Photography:
Accessibility: no, many stairs
Bibliography:
Address: Ryūsendō, 1-1 Aza Kannari, Iwaizumi, 027-0501 Iwaizumi-tyo, Tel: +81-194-22-2566, Fax: +81-194-22-5005.
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

1920s first exploration by locals.
19- to 28-AUG-1930 cave opened to the public by boat, 546 visitors in nine days.
1938 academic investigation of Ryusendo Cave.
14-DEC-1938 designated a National Natural Treasure.
1959 cave surveyed by local cavers.
1967 New Cave discovered.
1967 Speleological Research Institute of Japan established.
1975 Shindo Science Museum opened.
2011 LED light installed.

Description

photography
Entrance of Ryusendo. Public Domain.

Ryusen-do (Dragon Spring Cave) is named after its underground river. The cave is entered through a narrow but dry passage. This Hyakken Corridor was once flooded by water and in the early days it was visited by boat. The water flowed out the entrance, hence the spring in the name. Later a boardwalk was installed, but the cave river still flows below. That's the reason why the cave is sometimes closed due to flooding, after heavy rains the cave river raises and floods this passage.

After 500m the passage ends at the First Undergound Lake. There are numerous lakes in the cave, but the first three are part of the tour. The sumps have been partially explored by cave divers, but they are too deep for further exploration. The third is 98m deep and the fourth more than 120m and they are praised for the extremely clear blue water. Behind the third siphon the trail goes up a staircase to a fossil side branch named the Miharatoge Pass. A tunnel allows visitors to reach the surface.

Ryusen Cave is notable for the bats living in the cave. Five species of bats live in the cave, namely Greater horseshoe bat (Rhinolophus ferrumequinum nippon), Little Japanese horseshoe bat (Rhinolophus cornutus cornutus), Japanese Large-footed Bat (Myotis macrodactylus), Tube-nosed bat (Murina hilgendorfi), and Japanese long-eared bat (Plecotus sacrimontis). Among them are species who live outside during summer and hibernate during winter in the cave. The first two species live all year in the cave, during winter they also hibernate but they also roost in the cave and sleep during day in the cave while they hunt outside during the night. Also the endemic amphipod Eocrangonyx japonicus and the springtail Aphoromma nuda Yosii can be found in the cave.

On the other side of the road is the 龍泉新洞科学館 (Ryūsenshindō kagaku-kan - Ryusen Shinto Science Museum). The entrance to the museum is included in the cave ticket and it is a good place to spend some time waiting for the tour. It is actually a second cave which was first simply called New Cave (Shinto), as it was discovered in 1967 during the prefectural road widening construction. It was renamed because of the scientific value of its well-developed stalactites and the water course markings. It is entered through an artificial tunnel and shows dioramas of the Ryusen Shindo Man, prehistoric people who lived in the cave. They entered the cave through a natural entrance which is now the exit of the cave. The cave is separated from Ryusendo by a river and a valley, but both are most likely parts of a bigger cave system which existed before the river cut the valley so deep. There still exists a hydrological connection which runs underneath the Shiizu River without being connected to it.