Abukuma Cave – a beautiful, fantastic world created a long time ago
Naturally formed beauty created over the course of 80 million years.
Lining 600m of the cave is what is said to be the greatest number and variety of stalactites in Asia.
There’s a lot to see in Takine Goten, the largest hall in the cave, including the Tsuki no Sekai, which features the first light control system for stage productions ever introduced in a Japanese limestone cave.
Enjoy this mysterious and impressive underground fantasy world.
On this page you’ll find an overview of Abukuma Cave, what to wear, and safety precautions when entering the cave, to help you prepare before your visit.
For Visitors of Abukuma Cave
Clothing
You can enter the cave wearing normal clothes.
Safety Precautions when Visiting the Cave
There are some 300 steps leading down into the cave. We recommend you wear sports shoes.
The following persons should refrain from visiting the cave:
Persons using wheelchairs, persons with injuries, persons with walking difficulties, pregnant women, persons under the influence of alcohol, and persons with heart ailments
For Visitors to Irimizu Shonyudo
Clothing
You can take Course A while wearing normal clothing.
On Courses B and C, you will be walking through running water, so you should bring a change of clothing that you don’t mind getting wet.
The office at the entrance rents and sells candles, raincoats, rubber sandals, and other items.
Safety Precautions when Visiting the Cave
You will need a guide to enter Course C. For your safety, please do not stray from the course.
The inside of the cave is wet and slippery. Visitors are prohibited from entering the cave while wearing high heels, sandals, and the like.
The following persons should not visit the cave:
Persons using wheelchairs, persons with injuries, persons with walking disabilities, pregnant women, persons under the influence of alcohol, and persons with heart ailments
Irimizu Shonyudo has been designated as a National Natural Treasure. Acts that damage the cave are punishable by law.
Irimizu Shonyudo has been designated as a National Natural Treasure. In order to protect this cultural property, smoking is prohibited, as well as defacing, damaging, or taking stalactites. Any such acts are punishable by law.
Overview of Abukuma Cave
History
Abukuma was discovered in September 1969 on the site of the current Kamayama Quarry.
This region is a highland region called Abukuma-kochi. A karst plateau called the Sendai Plains stretches out on the western slopes of Mt. Otakinesan in the center of the highlands, and the region thrived on mining for limestone and marble since ancient times. Abukuma Cave was discovered while mining for limestone.
Operations in Kamayama Quarry ceased the year that Abukuma Cave was discovered, and the limestone outcropping that was the working face of the quarry now forms the side of the parking lot.
The entrance to the cave that was initially discovered was located near the current exit of the tourist portion of the cave. The cave itself is small at 12m deep and stretching 60m north and 15m east and west.
In March 1970, a survey team from Nihon University went to survey the caves and discovered that beyond the final opening at the northernmost end of the site was the main Abukuma Cave. In 1973, the cave was renovated for tourism and opened to the public.
Limestone outcrop next to the parking lot
Inside the cave
The standard tour route of Abukuma Cave is about 600m long.
About 150m from the entrance, the route branches off into the Discovery Route (120m), so in total the whole route is 720m.
The total length of the cave is 3,300m when including routes not generally open to the public, although this measurement may change based on future explorations.
Stalactites in a variety of shapes have developed here, and you’ll find stalagmites, stone pillars, cave shields (stalactites that are disc-shaped on top), and evidence of erosion from groundwater.
The temperature in the cave averages 15°C with little fluctuation year-round. However, looking closer at the data, in 1975 and 1977 (after the cave opened to tourism) the upper levels of the cave were 15 to 17°C in summer and 15°C in winter, while the lower levels were 14°C in summer and 0 to 10°C in winter.
Around the entrance, which is closer to outside temperatures, visitors can see icicles in winter, although the waterways and walls inside the cave do not freeze.
A survey in 2001 uncovered that the subterranean stream flowing from the deepest depths of the cave originated from groundwater seeping in from the foot of Mt. Otakinesan. The water is 9.3°C and is pH 8.1 (slightly basic).
Geology
A limestone layer called the Takine Layer is situated in the Abukuma-kochi region and runs 4km north and south, and 0.5 to 1.0km east and west. It stretches from the western slope of Mt. Otakinesan to the Ogoe area of Tamura City.
This limestone was formed from the remains of foraminifers and other organisms that were deposited on the bottom of the ocean from the Carboniferous Period to the Permian Period some 300 million years ago.
The limestone that forms Abukuma Cave is estimated to have transformed into crystalline limestone some 80 million years ago during the Upper Cretaceous Period.
Around that time, the Takine Layer limestone even further underground underwent contact metamorphism from the granite and granodiorite protruding in, which caused some of the limestone to crystallize (marbleize).
The limestone layer was exposed due to an extensive protrusion. It is estimated that the formation of the cave lasted from the end of the Tertiary Period into the Quaternary Period from when groundwater began eroding it. However, not all the details are clear.
Surrounding Geography
Exposed limestone called pinnacles are found all around Sendai Plains and give rise to the unique landscape of karst topography.
Aside from Abukuma Cave, there are sinkholes called dolines, Irimizu Shonyudo, and other caves nearby. Water oak and painted maple trees can be found in the large dolines, with moss spreading out on the forest floor.
The fall colors of the painted maple trees, and cherry blossoms in the spring are Sendai Plains’ seasonal attractions.
Japanese red pine is the dominant vegetation in the Abukuma Highlands overall, but deciduous tall trees like zelkova can be found on the Sendai Plains.
Small and medium sized mammals inhabit the area, including wild boar, raccoon dogs, and foxes.
