A National Historic Site important as a mound preceding standardized keyhole tombs. Investigations have established its form, surrounding ditch, and pottery chronology. It is part of the Makimuku Kofun Group.
Finds & research
Shonai-phase pottery and other material have been recovered from the ditch and mound fill. The burial facility is reported to have been lost, together with the upper mound, to levelling during the Second World War.
Official status & archaeological view
Official status
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).
Archaeological view
A keyhole-shaped mound at Ota, Sakurai, given in Sakurai City’s conservation plan as 96m (designation rationale), 99m (summary of investigations) and about 94m (site description); the Agency for Cultural Affairs describes the Makimuku group’s mounds as about 100m long. Its short front is characteristic of the Makimuku type. Pottery and other finds from the ditch suggest 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 burial facility is reported to have been largely destroyed, together with the upper mound, when an anti-aircraft gun emplacement was built during the Second World War.
Field notes
Most of the designated area is city-owned (including the grounds of Makimuku Elementary School), and part of the moat on the north side of the mound has been landscaped (Sakurai City). A school, housing and paddy fields lie around it, so do not enter private land or cultivated fields.