Square-ended keyhole mound (120m) in Jōganji-chō, Tenri City (Kayō cluster of the Yamato Kofun Group). The square-rear form is a rare variant of the standard keyhole mound, and this is one of the few large examples in the Yamato Kofun Group. It documents the diversity of burial forms in the early 3rd-century Yamato basin. Preserved as a Tenri City historic site.
Finds & research
Stone paving and wooden chamber (or vertical-shaft stone chamber) confirmed. Triangular-rimmed deity-and-beast mirrors and bronze objects reported among the grave goods.
Two views on the occupant
Archaeological view
Keyhole-with-square-rear mound (前方後方墳) 120m long. Late 3rd century. The square-ended mound (zenpokohofun) was a distinct contemporary variant of the keyhole form, surviving in relatively few examples nationally. As a constituent of the Yamato Kofun Group (Kayō branch), it documents the variety of burial forms at the dawn of the Yamato polity. Rear section ~80m per side, ~8m high. Burial chamber presumed to be a vertical-shaft or wooden-chamber tomb. Occupant unknown; likely a senior Yamato power-holder.
Imperial Household Agency view
Not designated by the IHA. National Historic Site managed by Tenri City as part of the Yamato Kofun Group. Not an imperial or reference site; archaeological investigation has been conducted.
Field notes
Large square-rear mounds are more common in eastern Japan, making this a rare example in the Yamato basin. Its presence hints that the 3rd-century Yamato polity was not monolithic but involved competing factions. Recommended as part of a Tenri City circuit alongside Andonyama, Shibuyamukaiyama, and Kurozuka kofun.