Hodota Burial Mounds

The Hotoda Kofun Group: Three Tombs of an Ancient Gunma Dynasty

Three grass-covered mounds stand within easy walking distance of one another in the farmland of northwestern Takasaki, in Gunma Prefecture. Together they make up the Hotoda Kofun Group, a set of large keyhole-shaped tombs raised over a span of only about thirty years, from the final decades of the fifth century into the opening years of the sixth. The mounds carry the names Futagoyama, Hachimanzuka, and Yakushizuka, and archaeologists believe they were built in that order, each for a successive ruler of the family that controlled the surrounding Kamitsukeno region.

A keyhole tomb, or zenpo-koen-fun, joins a round rear mound to a trapezoidal front platform. Seen from above, the combined outline resembles an old-fashioned keyhole. This shape was reserved for the highest ranks of early Japanese society, and the appearance of three such tombs in one small valley marks the area as a seat of unusual wealth and authority.

The site sits at the southern foot of Mount Haruna, a volcano whose eruptions would later bury much of the surrounding land in ash. That same volcanic soil preserved a great deal of what the tomb builders left behind, and the Hotoda mounds have become one of the clearest windows into the world of fifth-century eastern Japan.

A Ruling Family on the Edge of a Volcano

During the Kofun period, the plain at the foot of Mount Haruna supported a dense population of farmers working irrigated rice paddies. The family buried at Hotoda drew its power from this productive land. Excavations a short distance away uncovered the Mitsudera I site, a moated elite residence with a stone-faced enclosure and evidence of formal gardens and ritual space. Many researchers connect the people who lived at Mitsudera with the rulers entombed at Hotoda, giving the cemetery a rare partner: the home of the living and the resting place of the dead, both within sight of each other.

The three tombs were built quickly and in succession. Futagoyama came first, the largest of the group. Hachimanzuka followed, then Yakushizuka. By the time the last mound was finished, Mount Haruna had begun the violent activity that would define the early sixth century in this region. Ash from the eruption settled across the fields and into the tomb moats, and the timing can still be read in the ground: the outer moat of Yakushizuka contains a layer of volcanic ash, while its inner moat does not, which tells excavators that the eruption struck while the tomb was still being shaped.

Yakushizuka also carries fewer haniwa than the two earlier mounds. One reading of this difference is that the eruption had already drained the area of the labour and resources needed to furnish a tomb on the old scale. If so, the Hotoda group records not only the rise of a local dynasty but the moment its world was thrown into crisis.

Why the Mounds Are Protected

The Hotoda Kofun Group was designated a National Historic Site on 3 September 1985, with an expansion of the protected area on 27 August 2003. The designation recognises the group as an outstanding example of settlement and burial remains from the Kofun period.

Its value lies partly in what survives and partly in what has been recovered. All three tombs kept their boat-shaped stone coffins, and each was surrounded by double moats and dressed in fukiishi, the river stones laid over the slopes to give the mound a bright, deliberate surface. The figural haniwa found here, ranging from armoured warriors and shrine maidens to horses, boar, and waterfowl, are studied as some of the earliest and most complete haniwa tableaux in Japan.

The objects taken from Yakushizuka are protected separately. A bronze mirror, beads of agate and glass, and a set of gilt-bronze horse trappings recovered from that mound were designated an Important Cultural Property in 1939. Several of these pieces can now be seen at the museum beside the tombs.

Walking the Three Mounds

The most striking of the three is Hachimanzuka. Between 1996 and 1999 the city carried out a full reconstruction, returning the mound to something close to its fifth-century appearance. Where most kofun in Japan survive as quiet wooded hills, Hachimanzuka now shows its original face: slopes packed with pale river stones, two encircling moats, and four small round islands set within the inner moat, thought to have served as places for ritual.

Along the inner embankment stands the reconstructed haniwa arrangement, a band of fifty-four human and animal figures placed as they were found in excavation. Roughly six thousand plain cylindrical haniwa run around the mound and islands. Visitors can climb the rear mound and step down into a small chamber where a stone coffin is displayed, an unusually direct encounter with the burial heart of a kofun.

One haniwa from Hachimanzuka has drawn particular attention. It depicts a cormorant with a fish held in its beak and a bell fastened to a cord around its neck. The bell and cord are the marks of a trained bird, and the figure is read as evidence that ukai, fishing with cormorants, was already practised as ritual or livelihood in the Kofun period, centuries before the written records that describe it.

Futagoyama, the oldest and largest mound, has been preserved with planting rather than rebuilt, so it keeps the softer, green profile most visitors expect of a kofun. It measures about 108 metres along its length, with a rear mound 74 metres across and roughly 10 metres high, raised in three tiers. Its stone coffin has been reburied about a metre below the summit to protect it.

Yakushizuka lies within the grounds of Saikoji, a temple whose buildings and cemetery have cut away part of the mound over the centuries. According to the temple's own account, the stone coffin was opened in 1683 after a dream, and was found filled with vermilion and accompanied by grave goods and an image of Yakushi, the Buddha of healing. The mound and the temple's Yakushi hall take their name from that discovery. The boat-shaped coffin, carved from tuff, is kept under a shelter on the summit.

Around the Site

The two restored tombs sit inside Kamitsukenosato Park, a landscaped area of about thirteen hectares laid out around the cemetery. The park is open and free to walk at any time, and the wide lawns and the silhouette of Mount Haruna make it a pleasant place to spend an unhurried afternoon.

At the centre of the park is the Kamitsukenosato Museum, which gathers the finds from the tombs and the nearby Mitsudera residence. Models reconstruct the cemetery and the surrounding fifth-century landscape, and the figural haniwa, including pieces from the Important Cultural Property group, are displayed close enough to study in detail. A visit here first makes the walk among the mounds far easier to read.

The grounds also include the Tsuchiya Bunmei Memorial Literature Museum, devoted to a noted modern poet from the area. For those travelling by car, the site has ample parking. Reaching it by public transport from Takasaki Station is possible by local bus, though services are limited, so checking timetables in advance is worthwhile.