Shibetsu Ruins Group (Ichani Karikariusu Ruins/Kodo

An Unbroken 10,000-Year Chronicle

What makes the Shibetsu Site Cluster unique among archaeological sites in Japan is the extraordinary preservation of its surface remains. Because the cool, damp soil of eastern Hokkaido slows the natural infilling of ancient depressions, the pits left by collapsed pit dwellings remain visible from ground level even after thousands of years. Walking the trails of Po-Gawa Historical Nature Park, visitors can see the soft round hollows of Jomon-era homes overlapping with the squarer outlines of later Satsumon-era dwellings — generations of houses literally built atop the memories of those that came before.

Excavations have revealed pit dwellings spanning the entire arc of northern Japanese prehistory: the Jomon period (roughly 10,000 years ago through the late prehistoric era), the Continued Jomon culture, the Okhotsk culture (5th–9th centuries), the hybrid Tobinitai culture (9th–13th centuries), the Satsumon culture (7th–12th centuries), and finally the Ainu cultural period. Few places anywhere in the world offer such a continuous, visible record of human habitation in one location.

The Three Sites

The cluster designation brings together three distinct archaeological zones, each illuminating a different chapter of the region's deep past.

The Wooden Walkway Through Shibetsu Wetland

The approach to Ichani-Karikariusu leads visitors across the Shibetsu Wetland — itself a designated National Natural Monument — on a wooden boardwalk. In summer the marsh is studded with the blooms of rhododendron and lingonberry; in autumn the grasses turn a soft amber. This is no mere walking route: about 7,000 years ago this lowland was sea, and roughly 3,000 years later it became the wetland we see today. The board walk is, in effect, a stroll across deep geological time.

Pit Dwelling Depressions on the Forest Floor

Once you enter the oak forest beyond the wetland, the ground reveals itself as a vast palimpsest of human history. Soft circular hollows from the Jomon period are overlain by squarer Satsumon-era depressions; in places, three or four generations of dwelling pits overlap in a single spot. In late autumn after the leaves fall, or in winter when light snow dusts the forest, the contours of the pits become especially clear. Reconstructed pit dwellings have been built at certain points so visitors can imagine how the originals looked above ground.

The Visitor Center and Folk History Museum

The park's visitor center offers an essential introduction before walking the site, with displays on the natural environment, the archaeology, and the cultural history of the Shibetsu region. The adjoining Folk History Museum exhibits artifacts excavated from the site, including pottery, stone tools, and bone implements that bring the daily lives of these ancient peoples vividly to mind.

Pioneer Village (Kaitaku-no-Mura)

Adjacent to the visitor center stands a cluster of restored buildings from the Meiji-era settlement of Hokkaido — a school, a farmhouse, a sericulture building. Together with the prehistoric remains, the village allows visitors to trace human habitation in Shibetsu from 10,000 years ago to the modern era within a single afternoon's walk.

Guided Tours and Po River Canoeing

Specially trained guides from the Shibetsu Eco-Tourism Council lead walking tours of the wetland and archaeological sites by reservation. For something truly memorable, guided canoe trips on the Po River — one of the few primeval rivers in Japan that has never been straightened or dammed — let visitors paddle through landscapes virtually identical to those the prehistoric inhabitants would have known.

Hours and Admission

The Po-Gawa Historical Nature Park, which contains the Ichani-Karikariusu portion of the site cluster, is open from late April through late November (typically April 29 – November 23), with no closures during the open season. Hours are 9:00 to 16:30. Admission is approximately 330 yen for adults, 110 yen for high school and university students, and free for junior high school students and younger. The visitor center itself can be entered without charge. Note that the park is closed in winter, when the wetland and forest are blanketed in snow.

Getting There

By car, the park lies about 23 kilometers (a 30-minute drive) from Nakashibetsu Airport, the nearest commercial airport. By public transport, take an Akan Bus from JR Kushiro Station bound for Rausu, alight at the "Shiseki Shizen Koen Mae" stop, and walk a few minutes to the entrance. The bus journey is long — about two and a half hours — but passes through stunning eastern Hokkaido scenery.

A Note on Bears

Eastern Hokkaido is brown bear country, and the wooded approaches to Ichani-Karikariusu can occasionally be closed when bears are sighted. Visitors are strongly encouraged to check with the park staff at the visitor center before setting out, and to avoid the early morning and late evening hours. Walking with a guide is the safest option.