The buried founder of the Oiwayama lineage in Yasu. Though no mound survives, its outline is marked on the ground — an invisible kofun that opens Omi's kofun age. The pin marks the recorded site.
Finds & research
Omi ware and Tokai red-painted jar sherds from the moat; burial lost to leveling.
Two views on the occupant
Archaeological view
A 42m square-fronted mound (52m with moat), the oldest of the Oiwayama group (late 3rd century). Wholly leveled into paddies long ago, it was rediscovered as a buried monument in 1982; the burial itself was lost. Moat finds of Omi ware and Tokai red-painted jars show emergence-period Omi's eastern ties.
Imperial Household Agency view
Not designated by the IHA. Part of the National Historic Site "Oiwayama Kofun Group" (added 1985).
Field notes
The site is maintained with a ground-level display; combine with Kabutoyama (id:592) and Maruyama (id:600).