A Stone Age Site at the Foot of Mount Asama
The Tera-no-ura Stone Age Dwelling Site sits on a gentle south-facing hillside at roughly 770 meters elevation, in the Shigeno district of Komoro City, Nagano Prefecture. It looks today like an unassuming meadow rimmed by scattered boulders. Nearly a century ago, a small group of local schoolteachers digging into this slope uncovered a Late Jomon period house floor that helped open up the modern archaeology of the Mount Asama southern foothills.
The site was designated a National Historic Site (国史跡) on February 28, 1933, under the criterion covering shell mounds, settlement sites, burial mounds, and similar archaeological remains. It is one of two related National Historic Sites in the area; the other, the Inudate site (戌立遺跡), lies about 500 meters away across the Ōishizawa stream in present-day Tōmi City.
The 1930 Excavation
In the early Showa years, Japanese archaeology was still finding its institutional footing, and much of the field work in regional Nagano was carried out by schoolteachers and amateur scholars affiliated with district education associations. Around Mount Asama, members of the local history research group within the Kamisaku Education Association (上小教育会郷土史研究部) had been studying stone tools surfacing in the fields above Shigeno.
In April 1930 they excavated the Inudate site, and the following month, May 1930, they turned to Tera-no-ura. What they uncovered was the floor of a substantial dwelling: an outline measuring roughly 12 meters east-west by 12.8 meters north-south, two hearth traces, and three post holes. The size and the multiple hearths suggest that several houses of different dates likely overlapped on the same spot rather than one single enormous structure.
Pottery, Stone Tools, and a Wolf's Tooth
The objects recovered from the floor speak to a community deep into the Late Jomon period, roughly 4,500 to 3,300 years ago. Excavators collected sherds of Jomon pottery alongside a varied stone tool kit: chipped stone axes used for clearing and digging, polished stone axes for woodworking, stone arrowheads (sekizoku) for hunting, and grindstones for processing nuts and seeds. Pitted stones used for cracking hard shells or as anvils also turned up.
Among the more striking finds was a stone rod (sekibō), a phallic-shaped polished implement generally interpreted as a ritual object linked to fertility or community ceremony. A piece of animal bone identified as a wolf's fang was recovered as well, a reminder that the now-extinct Japanese wolf still roamed the highlands of central Honshu in the Jomon period.
Why It Was Designated, and What Remains Today
The designation came quickly. In February 1933, less than three years after the dig, the Tera-no-ura dwelling site was listed as a National Historic Site. Two factors mattered. First, the excavation, together with Inudate, became the starting point for serious study of Jomon culture along the southern flanks of Mount Asama, a field that has continued to expand ever since. Second, the way the site was preserved afterward set a precedent.
The excavated house floor was protected in place by a roof shelter built directly over it. This was a pioneering approach in Japan at the time, an early attempt at in-situ preservation rather than backfilling or removal of the finds. The shelter has since been lost, and the site today is essentially an open field with interpretive signage. Komoro City carried out a follow-up boundary-confirmation survey between 2014 and 2018 to better understand the extent of the remains.
For visitors, this means Tera-no-ura is best approached as a piece of intellectual history as much as a physical destination. Standing on the slope and reading what was found here, then traveling a short distance to the Asama Jomon Museum in nearby Miyota Town to see comparable artifacts, makes the experience cohere.
Visiting the Area
The site sits in farmland on the edge of the Shigeno settlement in Komoro City. The nearest railway station is Shigeno (滋野駅) on the Shinano Railway line, about 35 minutes on foot. Visitors arriving by car will find Komoro Interchange on the Jōshin-etsu Expressway a convenient access point. There are no on-site facilities; the location is largely a quiet rural setting with views toward the volcanic massif to the north.
The Asama Jōmon Museum (浅間縄文ミュージアム) in Miyota Town, about a fifteen-minute drive east, is the natural companion stop. Its collection includes Important Cultural Property pottery from the nearby Kawarada site and contextualizes the broader Jomon culture of the Asama foothills. For travelers building a longer itinerary, Komoro Castle's Kaikō-en garden and the Shakuson-ji temple at Nunobiki Kannon are within easy reach of central Komoro.
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Q&A
- When is the site open to visitors, and is there an admission fee?
- The site is an unrestricted outdoor location with no gates and no admission fee. It can be visited at any time, though the unimproved nature of the surroundings makes daylight hours practical.
- What is actually visible at the site today?
- The protective roof shelter built in the 1930s no longer stands. Visitors see an open field with informational signage. The substance of what was excavated here is best appreciated by reading the on-site interpretation or by visiting the Asama Jomon Museum in Miyota.
- How does the Late Jomon period relate to Japanese history more broadly?
- The Late Jomon spans roughly 4,500 to 3,300 years ago. Communities lived in pit dwellings, made elaborate pottery and ritual objects such as stone rods, and combined hunting and gathering with limited plant management.
- Why are Tera-no-ura and the nearby Inudate site both designated separately?
- Although close in distance, the two sites are physically separate occupation areas on either side of the Ōishizawa stream. Both were excavated in 1930 and designated together in 1933 as a paired record of Jomon settlement on the southern slope of Mount Asama.
- Can I see artifacts excavated from Tera-no-ura on display anywhere?
- The 1930 excavation finds are not on permanent public display at a single venue. The Asama Jomon Museum in Miyota Town offers context through comparable Late Jomon material from the same broader region.
Basic Information
| Name | Tera-no-ura Stone Age Dwelling Site (寺ノ浦石器時代住居跡) |
|---|---|
| Location | Tera-no-ura 3041 and 3049, Ōaza Shigeno-kō, Komoro City, Nagano Prefecture |
| Designation | National Historic Site (国指定史跡) |
| Designation Date | February 28, 1933 (Showa 8) |
| Designation Criterion | Settlement sites, burial mounds, and related archaeological remains |
| Period | Late Jōmon (approx. 4,500–3,300 years ago) |
| Dwelling Dimensions | Approx. 12 m (E–W) × 12.8 m (N–S) |
| Elevation | Approx. 770 m |
| Excavation | May 1930, by the Local History Research Group of the Kamisaku Education Association |
| Boundary Survey | 2014–2018, Komoro City Board of Education |
| Access | Approx. 35 min on foot from Shigeno Station (Shinano Railway); approx. 10 min by car from Komoro IC |
| On-site Facilities | Interpretive signage only; no restrooms or dedicated parking |
References
- Tera-no-ura Stone Age Dwelling Site - Komoro City Official Site
- https://www.city.komoro.lg.jp/soshikikarasagasu/kyoikuiinkaijimukyoku/bunkazai_shogaigakushuka/2/1/1/bunkazai/kunisitei/1040.html
- National Designated Cultural Properties Database (Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/bsys/maindetails/401/1170
- Comprehensive Database of Archaeological Site Reports Japan - Tera-no-ura Boundary Survey Report (2014-2018)
- https://sitereports.nabunken.go.jp/en/131358
- Asama Jōmon Museum (Miyota Town)
- https://w2.avis.ne.jp/~jomon/
Last verified: 2026.05.27