Artifacts Excavated from the Watanuki Kannonyama Tomb in

Watanuki Kannonyama Tumulus: An Unlooted Tomb and Its Grave Goods in Eastern Japan

In the late sixth century, a powerful figure of the Kamitsukeno region, a center of power in what is now Gunma Prefecture, was buried at the rear of a keyhole-shaped mound about 97 meters long, ringed by a double set of moats. The tomb sits in Watanuki, a district on the southern edge of Takasaki, and for some fourteen hundred years it held an unusual distinction: grave robbers never reached its burial chamber. When archaeologists worked through the site in five excavation campaigns beginning in 1967, they found the corridor-style stone chamber and its contents largely as they had been left.

What came out of that chamber, together with the clay figures that once stood on the mound above, is now grouped under a single designation as the excavated articles from the Watanuki Kannonyama Tumulus. The assemblage was named an Important Cultural Property in 1982 and raised to National Treasure status in 2020. It belongs to the national government and is displayed at the Gunma Prefectural Museum of History, a short distance from the tomb itself.

Why the find matters

Most large tombs of this period were emptied long ago, so an intact chamber is rare on its own. The Watanuki collection goes further. Many of its objects were either imported or made under direct foreign influence, evidence that a local lord in eastern Japan kept real ties to the continent and the Korean peninsula.

The clearest example is a bronze mirror decorated with a band of mythical beasts in low relief, a type known as a beast-band mirror. A mirror cast from the same mould was recovered from the tomb of King Muryeong of Baekje, in present-day Gongju, South Korea. That royal tomb shows strong influence from the Liang court of southern China, which places the Watanuki mirror within a wider network of exchange linking China, Baekje, and the plains of Gunma.

Two other objects point the same way. One is a bronze water vase of sahari, a tin-rich copper alloy, often described as the oldest known example of its kind in Japan and comparable to pieces from Northern Qi China. The other is an iron helmet topped with a small projection. Helmets used in the islands at this time were usually the visored shōkaku type without such a projection, so the form suggests a model drawn from the southern Korean peninsula.

The numbers fill out the picture. The chamber yielded 232 gilt-bronze objects, many of them horse trappings such as cloud-shaped ornaments, junction fittings, and pendant plaques, alongside nine gold and seven silver items, thirty-eight swords and blades, and eighty-four beads. For specialists, this combination of weapons, body armor, ornaments, and harness has few parallels anywhere in the country.

What to look for on a visit

The haniwa, the unglazed clay figures set on the mound, reward slow looking. The most celebrated piece is a group of three seated young women shaped as a single composition, the only example of its kind known in Japan. Around it stand other figures with distinct gestures: a man sitting cross-legged with his palms pressed together, a woman kneeling to offer a ritual vessel, and a woman holding out a leather bag. Warriors, horses, houses, shields, and roosters complete a cast that once lined the terraces of the tomb.

The scale of the burial chamber is its own argument for the owner's standing. The passage and chamber together run about 12.5 meters, with the chamber roughly 4 meters wide and 2.5 meters high. Its floor area matches that of the chamber in the Goseno Maruyama Kofun near Kashihara in Nara, a tomb often linked to Emperor Kinmei, though the Watanuki chamber stands about half as tall. The largest of its ceiling stones is said to weigh around 22 tons.

At the museum the objects appear as originals rather than replicas, in a room set aside for the National Treasure. Seeing the mirror, the helmet, and the figures gathered in one space makes the reach of this provincial court easy to grasp.

Around the site

The tomb and the museum lie a few kilometers apart in southern Takasaki. The mound has been laid out as a public archaeological park, the first of its kind in Gunma when it opened in 1981, and the restored stone chamber can be viewed on site. The museum stands in Gunma-no-Mori, a wooded park that also holds the Museum of Modern Art, Gunma, which makes the two an easy pairing for a half-day.

From JR Takasaki Station, the city Gururin loop bus reaches the museum in about thirty minutes from the east exit. Drivers will find roughly 480 free parking spaces, and the park lies about ten to fifteen minutes from several expressway interchanges. An hour is enough for the permanent galleries, a little more when a special exhibition is running.