A National Historic Site important as a mound preceding standardized keyhole tombs. Investigations have established its form, surrounding ditch, and pottery chronology.
Finds & research
Shonai-phase pottery and other material have been recovered from the ditch and mound fill. The central burial facility and grave goods are uninvestigated.
Two views on the occupant
Archaeological view
A keyhole-shaped mound at Ota, Sakurai, measured at about 96m in the national designation account and about 94m in Sakurai City’s conservation plan. Its short front is characteristic of the Makimuku type. Pottery from the ditch places its construction in the Shonai phase; the city reports both an early 3rd-century view and a view of construction in the mid-3rd century followed by burial later that century. The central burial facility remains unexcavated.
Imperial Household Agency view
This is not an Imperial Household Agency mausoleum. A component of the National Historic Site Makimuku Kofun Group (designated in 2006 together with Hokenoyama; Makimuku Yazuka and Katsuyama were added in February 2026).
Field notes
Because the historic site is surrounded by farmland, observe it from public roads and authorized areas without entering cultivated fields.