Artifacts Excavated from Butai Tomb No. 1, Gunma Prefecture

What Are the Butai No. 1 Tumulus Excavated Items?

The Excavated Items from Butai No. 1 Tumulus in Gunma Prefecture (Gunma-ken Butai Ichigōfun Shutsudohin) are a remarkable assemblage of artifacts unearthed from a late fifth-century burial mound that once stood in Arako-machi, Maebashi City. Designated as a National Important Cultural Property of Japan, the collection is owned by the State (Agency for Cultural Affairs) and is currently kept and displayed at the Gunma Prefectural Museum of History in Takasaki.

Butai No. 1 Tumulus was a scallop-shaped tomb (hotategai-shiki kofun) measuring approximately 42 meters in length. Excavation revealed house-shaped haniwa figures arrayed on a small rectangular projection attached to the round mound, cylindrical haniwa lining the mound itself, and—most remarkably—a rectangular pit packed with hundreds of miniature replicas carved from talc, alongside earthenware vessels bearing clay representations of food offerings. Few tombs offer such a vivid window into the rituals performed for the dead 1,500 years ago.

Gunma Prefecture, the heartland of ancient Kamitsukeno (Upper Keno), was the cultural center of eastern Japan during the Kofun Period. Over 13,000 burial mounds were built across this region, making it one of Japan's foremost "kofun kingdoms." The Butai No. 1 finds are an irreplaceable testimony to that rich spiritual world.

Historical Background — Where Burial Mounds Flourished

During the Kofun Period (3rd to 7th century CE), the area now known as Gunma maintained close ties with the Yamato court while developing a distinctive regional identity. More than 13,000 burial mounds were built here, and—remarkably—the production of haniwa clay figures continued in Gunma long after it had declined in the Kinki heartland.

The late fifth century, when Butai No. 1 Tumulus was constructed, was a transformative era. Tombs began to feature small rectangular "platforms" or "projections" (tsukuridashi) attached to the round mound, and these spaces became stages for elaborate funerary rituals. Butai No. 1 is one of the clearest examples of this new ritual architecture, with its offering pit and haniwa array preserved largely intact.

The tumulus once stood on the fertile alluvial plains of the Tone River basin, in what is today Arako-machi, Maebashi City. The mound's size and the richness of its finds suggest that a powerful local leader was laid to rest here, surrounded by the symbols of the community's prosperity.

Why It Was Designated an Important Cultural Property

The collection was designated a National Important Cultural Property because it allows researchers to reconstruct a fifth-century funerary ritual in striking detail. At many tombs, grave goods have been scattered or studied in isolation, but at Butai No. 1, the haniwa, the stone replicas, and the offering vessels were discovered together on a single ritual platform—preserving the choreography of an ancient ceremony.

Particularly notable is the rectangular pit containing miniature replicas carved from talc, a soft stone. These miniatures imitate everyday and ceremonial objects with great fidelity: 5 arrowheads, 2 sickles, 9 axes, 67 small knives (tōsu), 1 magatama (comma-shaped bead), 15 perforated discs, 202 small spool-shaped beads, and 2 wooden clog (geta) replicas. The sheer variety—over 300 pieces in total—is exceptional for a single tomb, and reveals the ancient practice of offering symbolic substitutes for real objects to the spirit of the deceased.

Equally important is the earthenware (haji-ware) found nearby, on which clay was modeled into the shapes of small fish, dumpling-like balls, and what appear to be nuts or seeds, all coated in red pigment. These are exceedingly rare three-dimensional depictions of food offerings, and they shed light on aspects of Kofun-period diet and ritual life that no written record could capture.

Highlights and Points of Interest

Nearby Attractions

The Gunma Prefectural Museum of History sits within Gunma no Mori (Forest of Gunma), an expansive public park that also houses the Museum of Modern Art, Gunma. The park offers a relaxing setting for a full day of culture, combining art, history, and nature within walking distance.

A short drive away lies Watanuki Kannonyama Kofun, a 97-meter keyhole-shaped tomb whose untouched stone chamber yielded the remarkable hoard now designated a National Treasure. Further afield, the Ota Tenjinyama Kofun in Ota City—at 210 meters, the largest in eastern Japan—and the beautifully reconstructed Hodota Hachimanzuka Kofun in Takasaki offer immersive encounters with the kofun landscape.

Central Takasaki adds further variety: the towering White Robe Kannon statue, the Shōrinzan Daruma-ji Temple (birthplace of the Takasaki daruma doll), and a vibrant local food scene featuring "okkirikomi" noodle stew make this city an excellent base for exploring the region.