Arafune Cold Storage, located in the mountains of Shimonita, Gunma Prefecture, is the remains of a facility that used cold air flowing from gaps between rocks to store silkworm eggs known as sanshu.
Although it is not a tourist destination with large surviving buildings, the stonework remains and cold air that can still be felt offer a tangible look at the ingenuity that supported Japanese sericulture.
The site is on a mountainside, and information about visiting conditions, traffic restrictions, and wildlife may change.
Before setting out, check the site's opening status and access information for the day.
What Is Arafune Cold Storage? | A Natural Refrigeration Facility Supporting a World Heritage Site
The value of Arafune Cold Storage lies in how natural cold air was linked to sericulture technology.
Understanding that the facility was used to regulate when silkworms developed makes the meaning of its stonework easier to grasp than viewing the remains alone.
A Component of the Tomioka Silk Mill and Related Sites
Arafune Cold Storage is a World Heritage component of the “Tomioka Silk Mill and Related Sites,” together with Tomioka Silk Mill, the Tajima Yahei Sericulture Farm, and the Takayama-sha Sericulture School.
Through their different roles in raising silkworms, storing silkworm eggs, teaching techniques, and reeling silk, the four sites illustrate the system that supported mass production of raw silk.
When visiting Arafune Cold Storage, it is important to see it not as an isolated refrigeration facility but as one stage connecting Gunma's silk industry.
Cooling Silkworm Eggs to Control Hatching
Sanshu are silkworm eggs that hatch into the silkworms that make cocoons, the raw material for silk thread.
Storing silkworm eggs in a cold environment made it possible to control when they hatched, helping sericulture, then practiced once a year, to be carried out several times in step with the seasons.
A defining feature of Arafune Cold Storage is that it used the mountain's natural conditions as production technology before electric refrigeration became widespread.
How Cold Air Forms Between the Rocks
Spaces inside the rocks piled on the slope allow air to pass through, and cold air flows out from them.
At Arafune Cold Storage, stone walls were built where this cold air emerged, and storerooms were placed above them to hold silkworm eggs.
Today, stonework rather than buildings is the main feature, but visitors can physically sense how the natural environment and human technology came together here.
Stonework Highlights | Imagine the Cold Air and the Site in Operation
At the site, the remaining stonework and terrain provide clues for imagining the facilities when they were operating.
Interpretive panels and explanations from on-site guides make it easier to understand the role of each area even though no buildings remain.
Three Cold-Storage Structures Along the Slope
Arafune Cold Storage consists of structures Nos. 1, 2, and 3, where the stone foundations of the former storerooms remain today.
Following the arrangement of the stonework reveals how the facility expanded by making use of the mountainside and the places where cold air emerged.
Viewing the entire site from the visitor plaza before approaching the nearby remains makes the positions of the three structures easier to understand.
Experience the Cold Air on Your Skin
At Arafune Cold Storage, cold air produced by the same natural conditions as during its operating years continues to flow today.
When the temperature difference from the outside air is large, white mist-like vapor may appear between the stones, but it depends on weather conditions and is not guaranteed.
Paying attention to the wind direction and changes in the air helps visitors appreciate why this location was chosen.
Observe from the Open Area Without Entering
To protect the stonework and ensure safety, visitors cannot enter the cold-storage structures.
Stay within the permitted area, do not touch the stones or step onto the slope, and observe from the designated paths and plaza.
Restrictions that preserve the site as archaeological remains are also part of the effort to pass this World Heritage property on to future generations.
History of Arafune Cold Storage | The Innovation That Enabled Multiple Sericulture Cycles
Learning the history of Arafune Cold Storage shows how stonework in the mountains was connected to local industry and distribution within and beyond Japan.
The discovery of a natural phenomenon and its development into a storage facility provide important context for a visit.
The Silkworm-Egg Storage Facility Built by Seitarō Niwaya
Arafune Cold Storage was built by Seitarō Niwaya and his son Senju, who was responsible for selecting the cold-storage site, planning it, and managing operations.
Structure No. 1 began operating in 1905 (Meiji 38), No. 2 in 1908 (Meiji 41), and No. 3 in 1914 (Taishō 3).
It is said that they focused on the cold air flowing between the rocks and built the storage facility by applying knowledge of weather, sericulture, and civil engineering.
The technical ingenuity lay not in using the natural terrain unchanged, but in combining stonework and buildings to harness the temperature environment for production.
Silkworm-Egg Trade Across Japan and Beyond
With three structures, Arafune Cold Storage had Japan's largest storage capacity at the time. Confirmed requests to store silkworm eggs came from 40 regions across Japan, as well as from the Korean Peninsula.
Its links to a wide area despite its mountain location show that silkworm eggs were an important commodity and the starting point of sericulture.
The contrast between the quiet landscape today and the history of large-scale distribution is one of Arafune Cold Storage's distinctive attractions.
Connection with Tomioka Silk Mill
Tomioka Silk Mill handled the stage of producing raw silk from cocoons, while Arafune Cold Storage stored silkworm eggs at an earlier stage.
Considering this alongside the sericulture techniques represented by the Takayama-sha Sericulture School and the Tajima Yahei Sericulture Farm reveals how the four sites divided their roles and contributed to the development of the silk industry.
When touring several sites, understanding whether each one represents “eggs, rearing, education, or silk reeling” will deepen your appreciation.
Visiting Hours, Admission Fees, and Opening Information
Standard visiting conditions are established, but temporary changes may be made because of the natural environment or safety measures.
The following is standard information, so check the site's opening status for the day of your visit before setting out.
| Item | Basic Information | Before You Visit |
|---|---|---|
| Visiting hours | 9:30–16:00 | Last admission at 15:30 |
| Winter closure | December 1–March 31 | Closed to visitors during this period |
| Admission fee | Adults: 500 yen | Free for high school students and younger |
| On-site guide | Free | Advance reservation required for groups |
Payment and Free Admission
Admission is 500 yen for adults and free for high school students and younger, Shimonita residents, and holders of disability certificates.
Payment by PayPay is accepted in addition to cash.
Guides and Visitor Plaza Facilities
Guides are stationed at the site during visiting hours and provide explanations free of charge.
Groups wishing to receive a guided explanation must make an advance reservation with the Shimonita Town History Museum.
The visitor plaza has restrooms, a cold-air experience room, vending machines, a rest area, and accessible parking. Ask a guide to use the AED.
How to Get to Arafune Cold Storage | Car, Taxi, and Shuttle Bus
Arafune Cold Storage is in a mountainous area, so access conditions differ from those of a typical urban tourist facility.
Because the roads are narrow and traffic restrictions apply, it is important not to rely solely on car navigation and to confirm the correct route for the day of the week.
Check the Route for Your Day When Driving
By car, approach from the Shimonita Interchange on the Jōshin-etsu Expressway.
On weekends and public holidays, the standard route via Kōzu Farm (about 24 km) is recommended. The Yashiki Route (about 19 km), available only on weekdays, is narrow and cannot accommodate buses.
Sightseeing Taxi from Shimonita Station
When using public transportation, you can take a sightseeing taxi from Shimonita Station on the Jōshin Electric Railway.
The site is not within walking distance directly from the railway station, so arranging round-trip transportation in advance provides peace of mind.
If using a sightseeing taxi, confirm operating conditions and availability in advance.
Free Shuttle Bus on Operating Days
A free shuttle bus runs from Parking Lot No. 1 to the visitor plaza on weekends and public holidays from April through November, as well as on weekdays during Golden Week and the Obon period.
It operates from 9:30 to 15:50 and covers the approximately 800 m between Parking Lot No. 1 and the visitor plaza.
Service is limited to weekends, public holidays, and specified periods, so check the timetable for your visit date.
If you do not use the shuttle bus, you will walk on a slope, so allow enough time and stamina for the uphill return journey as well.
What to Wear and Wildlife Precautions
Visiting Arafune Cold Storage requires preparation for walking around a mountain historic site rather than touring a developed indoor exhibition.
Keep both the protection of cultural property and your own safety in mind.
Choose Athletic Shoes and Comfortable Clothing
There is a slope with elevation changes from the parking area to the site, and the historic site also has stairs, inclines, and places where loose stones can be slippery.
Stable athletic shoes and comfortable clothing are recommended, and packing your belongings so both hands remain free will make walking easier.
Because conditions may feel different where cold air flows and in direct sunlight, a layer that can be adjusted to the temperature is also useful.
Prepare for Bears and Other Wildlife
Bears, deer, wild boars, and other wildlife inhabit the surrounding area.
Carry something that makes noise, such as a bear bell or radio, and take all trash with you.
Sightings and closure measures may change, so follow on-site notices and staff instructions, and do not enter restricted areas.
Visitor Etiquette for Protecting the Remains
The stonework and surrounding nature are both things to view and protected cultural property.
Stay on the visitor paths, do not collect plants, and do not leave trash.
When taking photos, do not block passageways. If you see wildlife, do not approach it or use flash photography.
Learn More at the Shimonita Town History Museum
If it is difficult to imagine the site's former appearance from the stonework alone, consider viewing the exhibits at the Shimonita Town History Museum first.
Learning the background before visiting the site makes it easier to connect the explanations along the path with the layout of the remains.
Learn About Operations Through Shunshūkan Materials
The Shimonita Town History Museum displays materials about Shunshūkan, the organization that operated Arafune Cold Storage, as well as dioramas that reconstruct its appearance at its peak.
This helps visitors understand Arafune Cold Storage not only as a source of natural cold air but also as a business that received, stored, and shipped silkworm eggs.
A reciprocal discount using admission ticket stubs is available between Arafune Cold Storage and the museum, so check the conditions at the reception desk.
Use the Multilingual Brochure
Shimonita Town publishes a multilingual brochure about Arafune Cold Storage.
If someone in your group is not comfortable with Japanese, checking materials in a supported language before the visit will make it easier to share the on-site explanations.
Combining translated materials with on-site guidance helps visitors understand how the cold air works and the terminology of sericulture.
Summary | Trace the Wisdom of Nature and the Silk Industry at Arafune Cold Storage
Arafune Cold Storage is a World Heritage component that used cold mountain air to store silkworm eggs and supported sericulture and raw-silk production in Gunma.
Keeping in mind the three stone structures, the cold air that still flows, and the site's connection with the roles of Tomioka Silk Mill and the other properties makes it easier to appreciate the value of these remains without surviving buildings.
Wear clothing suitable for mountain paths, and check opening status, shuttle bus service, traffic restrictions, and wildlife information before visiting.
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