A Stone Age home on a Gunma mountainside
In 1935, work on a hillside in the Oana district of Minakami exposed a ring of flat river stones lying about a metre beneath the surface. Two years later a second, larger stone floor came to light roughly 100 metres away, on the far side of a small valley stream. Together these two finds make up the Minakami Stone Age Dwelling Site, the remains of homes built and lived in during the Jomon period, Japan's long age of hunter-gatherers.
Minakami is a mountain town in the far north of Gunma Prefecture, close to the prefectural border and the upper reaches of the Tone River. Most travellers come for its hot springs, its rafting, or the peaks of Tanigawa-dake. The dwelling site is a quieter stop. What it preserves is unusual: a Jomon home set not on an open plain or a coastal terrace, but partway up a wooded slope.
What a stone-paved dwelling was
Jomon people generally lived in pit dwellings, with a floor dug down into the earth and a thatched roof raised above it. From the closing centuries of the period a particular variation appeared across the mountainous parts of the Kanto and central regions: the stone-paved dwelling.
In these homes the floor was covered with stones, from fist-sized cobbles to slabs an adult could barely lift, set flat and fitted together. Many examples have a rounded main room with a short projecting passage at the entrance, so that the plan resembles an old hand mirror with its handle. Roof posts stood close against the walls, and a hearth built of set stones occupied the centre of the room. What these buildings were for is still debated. Some were certainly dwellings; others may have served the community for ritual gatherings.
Both floors at Minakami belong to this tradition. The larger of the two is thought to be a mirror-handle stone-paved dwelling of the kind built throughout the surrounding highlands.
Why the site was protected
The remains were recorded with care soon after they were found. The earlier floor, at a place called Sakaue, sat about a metre down. Its river stones formed a rough oval measuring around 1.4 metres east to west and 2 metres north to south. Near the centre lay a rectangular hearth bordered by stones, about 40 by 30 centimetres and some 18 centimetres deep. Seventy centimetres to the south of the hearth, a jar-shaped earthenware vessel had been set into the ground.
The second floor, at Okubo, lay deeper, close to 1.8 metres below the surface. Its paving formed a wider oval, roughly 3.8 metres east to west by 3 metres north to south, again with a rectangular hearth at its heart. Stone tools and Jomon earthenware were recovered from both floors and the ground around them, and finds from the site include stone axes, stone grinding slabs and arrowheads.
In 1944 the two floors were designated a National Historic Site, singled out as a clear and notable example of a Stone Age dwelling surviving in mountain terrain. A further area was added to the designation in 2017, and the protected ground now covers about 2,197 square metres. The Agency for Cultural Affairs records the site as dating to the very end of the Middle Jomon. Stone-paved dwellings of this form span the late Middle and Late Jomon, and some guides describe the Minakami homes as Late Jomon.
Visiting the two floors
Each stone floor is sheltered by its own small wooden building, put up to protect the remains from weather and erosion. Visitors do not go inside. You look in through windows set into the shelter walls, down onto the stones much as they were left after excavation.
The two shelters stand about 100 metres apart, separated by the stream that runs down the slope. The Sakaue floor, the first found, is the smaller and is sometimes called the No. 1 dwelling; the Okubo floor is the larger No. 2 dwelling. Seeing them in sequence makes the difference in scale plain.
It is worth pausing over the setting. A home halfway up a forested slope, well above the river, is not where most people picture Jomon life. Standing at the window, with the stream audible below, you are left to wonder why this particular ledge was chosen, and what the daily walk to water and hunting grounds was like. Signage on site is sparse, so a little reading beforehand helps.
Around Minakami
The dwelling site sits within easy reach of the wider attractions of Minakami. The town is the gateway to Tanigawa-dake, a mountain popular with hikers and, in autumn, with leaf-viewers riding the ropeway. The Tone River that runs below the site is one of Japan's best-known rivers for rafting and canyoning in the warmer months.
Minakami is also a long-established hot-spring district, with several onsen villages strung along the valley. The Suwakyo gorge, a short distance downstream, offers riverside walks and a suspension bridge, and serves as a base for bungee jumping. A stop at the roadside station in town is a practical way to combine the prehistoric site with local food and produce.
- 📍 Plan Your Visit to Gunma
- Find tours, activities & transport passes near Water Stone Age Dwelling Site
- [ Kusatsu Onsen & Tomioka Silk Mill Heritage Tours ]
Q&A
- Can I go inside the dwelling remains?
- No. Each stone floor is enclosed in a protective shelter, and the remains are viewed through windows in the shelter walls. There is no admission building and no charge.
- How do I reach the site?
- It lies in the Oana district of Minakami. By car it is about five minutes from Minakami Station on the JR Joetsu Line. By bus the nearest stop is Oana Choei Jutaku Iriguchi, but services are infrequent, so check times in advance.
- What is the difference between the two parts of the site?
- They are two separate dwelling floors about 100 metres apart, on opposite sides of a small stream. The Sakaue floor (No. 1) is the smaller and was found in 1935; the Okubo floor (No. 2) is larger and was found in 1937.
- What was found at the site?
- Besides the stone-paved floors and their central hearths, excavation recovered a buried jar-shaped vessel, Jomon earthenware, stone axes, stone grinding slabs and arrowheads.
- How old are the dwellings?
- They belong to the Jomon period. The Agency for Cultural Affairs records the site as dating to the end of the Middle Jomon, several thousand years ago; the stone-paved dwelling form continued into the Late Jomon.
Basic Information
| Name | Minakami Stone Age Dwelling Site (Minakami Sekki Jidai Jukyo Ato) |
|---|---|
| Location | Oana, Minakami, Tone District, Gunma Prefecture |
| Designation | National Historic Site |
| Date designated | 13 November 1944 (area added 9 February 2017) |
| Period | Jomon period (end of Middle Jomon) |
| Protected area | Approx. 2,196.89 m² |
| Components | Two stone-paved dwelling floors (Sakaue / Okubo) |
| Access | About 5 minutes by car from Minakami Station (JR Joetsu Line) |
| Viewing | Through the windows of protective shelters; freely accessible |
References
- Database of National Cultural Properties, Agency for Cultural Affairs
- https://kunishitei.bunka.go.jp/bsys/maindetails/401/557
- Cultural Heritage Online, Agency for Cultural Affairs
- https://bunka.nii.ac.jp/heritages/detail/190352
- National Historic Site Guide (Kotobank)
- https://kotobank.jp/word/水上石器時代住居跡-1445104
- Minakami Tourism Association, Minakami Perfect Guide
- https://www.enjoy-minakami.jp/place.php?itemid=560
Last verified: 2026.05.22