No excavation permitted under IHA mausoleum regulations. Internal structure and grave goods remain unknown. Exterior viewable from public paths.
Two views on the occupant
Archaeological view
Actual occupant unknown. 207m keyhole mound.
Imperial Household Agency view
Managed by IHA as the mausoleum of Princess Hibasu-hime.
Field notes
The name "Mimasagiyama" literally means 'mausoleum hill,' showing it has long been recognized as an imperial tomb. According to the chronicles, the funeral of Princess Hibasu-hime marked the abolition of the practice of live burial, replaced by the custom of setting up haniwa figures.