Marukoyama Kofun: Asuka's Unusual Six-Sided Tomb
A restored late seventh-century tomb mound whose six-sided plan stands apart from the round and square forms visitors often expect in Asuka.
Verified site photographs are being prepared.Discover Marukoyama Kofun: Asuka's Unusual Six-Sided Tomb
Marukoyama Kofun sits on the southern slope of the Mayumi hills, in the landscape of small tombs west of Asuka's best-known central sites. Excavation revealed a polygonal mound with six sides, a rare shape that helps show how elite burials changed near the end of the Asuka period. Archaeologists also traced a long drain that carries hillside water away from the mound, an important piece of engineering in this sloping setting. The chamber itself is a stone-built, plastered burial structure and is not open to visitors. The mound is the experience here: look at its reconstructed outline, then compare its form with nearby tombs rather than expecting a mural chamber or an interior visit. The identity of the person buried here remains uncertain; an imperial prince is one theory, not a settled fact.
Read the shape before the story
Asuka Village identifies Marukoyama as a late seventh-century terminal-period tomb. Its official cultural-property description gives an approximately 24-metre diagonal span and a height of about 4.5 metres, with a polygonal mound built in two stages. The village tourism page emphasizes that excavation showed it to be hexagonal. This geometry is the clearest thing a visitor can take away from the site: it differs from the more familiar circular kofun and points to the distinctive burial forms of the period's ruling elite.
Understand what archaeology found
The village describes a cut-tuff, horizontal-entry stone burial chamber with plaster on its inner surfaces, plus a stone-paved outer feature and drainage works. Finds included fragments of a dry-lacquer coffin, metal fittings and beads. The remains help explain construction and funerary practice even though the chamber cannot be entered. No mural paintings are reported for this tomb, so it should not be confused with the painted chambers at Takamatsuzuka or Kitora.
Notice how the builders managed water
Asuka Village's fourth excavation summary records gravel paving and an underground drain along the rear cut, with the combined known drain measuring more than 40 metres. The report explains that it was designed to divert water flowing down from the hillside. This hidden infrastructure is part of the tomb's story: the builders had to stabilize and protect a chamber cut into a sloping ridge, not only shape a six-sided mound.
Keep the proposed occupant uncertain
The official village record mentions a theory that the tomb belonged to a son of Emperor Tenmu. The tourism association describes the polygonal form as suggesting a member of the imperial family. These are archaeological interpretations rather than an identified occupant. The name and shape are secure parts of the guide; the person's identity is not. That open question makes Marukoyama useful beside nearby tombs, where researchers also weigh shape, scale, construction and burial objects.
See the mound respectfully
The Asuka tourism association lists the site in its Takamatsuzuka area and provides an official map embed centered on the tomb. Its volunteer guide publishes a roughly five-kilometre, three-hour west-Asuka route from Asuka Station via Marukoyama, Iwayayama, Kengoshizuka, Numayama and Masuda Iwafune to Okadera Station. That is a multi-stop guided itinerary, not the direct time or distance to this mound; check current route and guide availability. The official pages reviewed do not give a visitor-service schedule, toilets, parking, step-free route or a staffed reception point. Remain on public paths, respect nearby homes and farmland, and do not enter or climb protected features unless signs explicitly allow it.
Pair it with the nearby tomb landscape
Marukoyama is most rewarding as one chapter in a Mayumi–Takamatsuzuka area visit. The village's official page places it among the Asuka tombs and lists nearby Kengoshizuka, Iwayayama, Nakaoyama and the Takamatsuzuka area. Select only the tombs you can reach comfortably and check each one's access separately: some mounds can be viewed outside, while burial chambers are protected and closed. Check current route conditions, weather and daylight before setting out, especially if combining rural lanes and cycling.
What to look for
A rare six-sided mound, reconstructed after archaeological investigation
Late seventh-century tomb with a cut-stone chamber that is not open to visitors
The occupant is debated; compare the site with nearby tombs without treating a theory as fact
Photo notes
No MyNara-licensed image is attached. Images on the Asuka Village cultural-property pages have not been copied. Follow posted rules and avoid entering private farmland or photographing residents without permission.
Make a day of it
Explore guides close to this map point, then check the actual route before travelling. Distances below are straight lines, not walking distances or travel times; map points may not be entrances.
Sources & editorial status
Original MyNara draft based on the linked sources. Sources reviewed 20 October 2026. Opening arrangements, prices and offers may change; use the operator's current information before travelling.
- Asuka Village — designated historic site record for Marukoyama Kofun, location, dimensions, construction and finds
- Asuka Village Tourism Association — Marukoyama Kofun visitor entry and map embed
- Asuka Village — excavation and structural research notes for Marukoyama Kofun
- Koto Asuka Preservation Foundation — cross-reference for mound form, finds and location
- Asuka Tourism Association volunteer-guide routes — west Asuka, about 5 km / 3 hours