Yatani Tomb

A Burial Mound That Belongs to Two Worlds at Once

On a low hill at roughly 230 meters elevation, on the southern rim of the Miyoshi Basin in northern Hiroshima Prefecture, sits a small earthen mound with an unusual problem of identity. Its official name is Yatani Kofun, the word kofun meaning an ancient tumulus of the sort that spread across Japan from the third century onward. Yet archaeologists who have studied it now place it slightly earlier, in the closing years of the Yayoi period, and prefer the term funkyubo, a mounded burial. The monument was built around 1,700 years ago, at the threshold between two eras, and it carries traits of both.

The mound measures 18.5 meters along its main axis and rises about 1.2 meters above the hill. Counting the shallow ditch that encircles it, the whole structure spans 22.6 meters. Those are modest figures, but within the Chugoku Mountains this is the largest Yayoi-period mounded burial known, and its shape has kept it in the academic literature for half a century.

The form is what makes it strange. The corners of the mound flare outward into pointed projections, a style called yosumi tosshutsu-gata, the four-corner projecting type. But the eastern side narrows into a waist, so that the outline as a whole resembles two shapes joined: a square rear platform and a smaller forward extension. Stand at the edge and the mound reads almost as a single squared figure with a tail, the angular ancestor of the keyhole tombs that would soon dominate the islands.

Found by Accident, Read Carefully

Yatani came to light because of a bulldozer. Between 1977 and 1979, the hills east of the city were being leveled for the Miyoshi Industrial Park, and the construction work exposed traces of an old burial ground. The Hiroshima Prefecture Board of Education carried out a full excavation before the site could be lost. What they uncovered was not one tomb but a cluster.

The mound sits within a broader scatter of remains known as the Matsugasako site group, a stretch of hillside used by people from the Jomon period through the Kofun period. Yatani is the centerpiece. To its west the excavators found two square moated burial plots, partly collapsed, and on the eastern slope of the same hill a kiln that had fired Sue stoneware during the later Kofun period. The hill, in other words, served the living and the dead across many centuries, and the 1979 designation as a National Historic Site covers the burial complex as a whole, an area of about 13,100 square meters.

The builders shaped the mound by cutting into the natural ridge and packing earth on top. They faced the sloping sides with stones laid flat against the surface and edged the base with a line of upright stones. A ditch about two meters wide followed the outline of the mound. This is careful, deliberate construction, and the labor it represents tells you the person buried at the center mattered to the community that raised it.

Why the Shape Matters: A Meeting of Izumo and Kibi

The reason Yatani earned national protection has less to do with its size than with what its details reveal about ancient geography. Two pieces of evidence pull in different directions, and that tension is the point.

The four-corner projecting mound is a regional signature. Burials of this type cluster around Izumo, in present-day Shimane, and along the Japan Sea coast. They belong to the cultural world of the San'in region, north of the mountains. Yatani's projecting corners place it firmly in that tradition.

The pottery says something else. From the encircling ditch, excavators recovered fragments of tokushu kidai and tokushu tsubo, the ornate pedestals and jars used as offering vessels at high-status burials. These vessels are a hallmark of the Kibi region, the area around modern Okayama on the Inland Sea side of the mountains. Analysis of the clay showed it matched material from southern Kibi. Some of the pedestals and jars were coated in red pigment and made at considerable size.

So the grave form looks north to Izumo while the ceremonial pottery looks south to Kibi. Miyoshi lies in the basin between them, on the routes that linked the two. The people buried at Yatani drew on customs from both directions, and the monument records a community that sat at a cultural crossroads in the generations just before a unified tomb culture took hold. For understanding how local society worked before the Kofun period proper, that makes it a rare and valuable document.

What to Look For on the Mound

Yatani has been restored and laid out for visitors, with the burial positions marked on the surface, so a walk across it is also a walk through the structure the archaeologists recorded.

Eleven burials were found in the mound. The earliest and most important is a large pit near the center, roughly four meters square, which once held an assembled wooden coffin. Inside, the excavators found cinnabar, the vivid red mercury mineral scattered over high-ranking burials as a protective and ritual substance. With it lay five tubular beads of jasper and three small glass beads. Around this central grave, ten further burials were added over time, in wooden coffins, stone cists, and earthenware containers. A few yielded iron objects: a planing tool and fragments of small knives, modest goods that still signal status in an age when iron was scarce.

The most surprising find came not from the mound itself but from the moated plots beside it. Small glass beads recovered there were studied for their chemical makeup, and the glass proved to have been made with natron, a mineral flux characteristic of glassmaking in the ancient Roman world. Specialists identified the beads as products that originated in the Roman Empire. How they reached a hilltop in inland Hiroshima is a question the beads cannot answer on their own, but they are a quiet reminder that long-distance exchange networks touched even small communities in third-century Japan.

The objects themselves are not kept on the hill. Stand on the restored mound and what you see is the architecture: the squared platform, the narrowed waist, the projecting corners, the stone facing at the base. It is best appreciated slowly, with the explanatory panel installed by the city to orient you.

Planning a Visit

Yatani sits inside the Miyoshi Industrial Park, which is less scenic than the name "ancient burial mound" might suggest, and finding it takes a little patience. A small parking area lies on the southwest side of the mound, and a marked path leads up to a stone post and the restored monument. Drivers usually come from the Miyoshi interchange on the Chugoku Expressway, following Route 375. By public transport, the nearest stop is the Miyoshi Industrial Park bus stop on the Bihoku Kotsu service, a walk of only a few minutes.

The site is open ground with no admission fee and no fixed hours. There are no facilities on the hill itself, so it works best as a focused stop of fifteen to thirty minutes rather than a destination for a full afternoon. Sturdy shoes are sensible, and the panel on site repays a careful read, since the mound's meaning is far easier to grasp once you know what its odd outline is telling you.

Nearby: One of Japan's Great Tomb Landscapes

Yatani makes most sense paired with the museum that holds its finds. About three kilometers to the southeast lies Miyoshi Fudoki-no-oka, a field museum covering some 30 hectares of hillside. Its centerpiece is the Jorakuji-Nanatsuzuka tumulus group, a National Historic Site with 176 burial mounds of the fifth and sixth centuries, among the largest such concentrations in the Chugoku region. Walking trails thread between the mounds, and the park also preserves reconstructed ancient dwellings, rebuilt stone chambers, and the former Mano family residence, an Important Cultural Property farmhouse.

Within the park, the Hiroshima Prefectural Museum of History and Folklore displays the objects excavated at Yatani, including the jasper beads, the iron tools, and the Kibi-style offering vessels. The artifacts were designated an Important Cultural Property in 1994. Seeing the mound and then the things drawn from it, or the reverse, gives a far fuller picture than either visit alone.

The Miyoshi Basin itself is worth lingering in. The city stands where several rivers converge, and on cool autumn mornings the valley fills with a sea of fog that locals prize. The same rivers and gentle hills that drew settlers 1,700 years ago still shape the landscape today.