Beside Kounji Temple in Muraida, Maibara, this site is designated as the mausoleum of Okinaga Hirohime, consort of Emperor Bidatsu. The stone coffin and haniwa discovered during temple works provide evidence for considering the mound’s date alongside the mausoleum tradition.
Finds & research
A stone coffin and enclosure were found during the 1696 Kounji Temple works. Later repairs to the hall platform wall yielded many haniwa dated to around the end of the 5th century.
Official status & archaeological view
Official status
Managed by the IHA as the Okinaga Mausoleum, designated as the tomb of Hirohime, consort of Emperor Bidatsu. The mausoleum was arranged in the Meiji period.
Attribution (jitei): the Imperial Household Agency's determination of whose tomb it manages — separate from heritage designation.
Archaeological view
Maibara City reports that a coffin and stone enclosure were found during temple works in 1696, and haniwa appeared during later repairs. The haniwa and house-shaped coffin are dated to around the end of the 5th century, earlier than Hirohime’s later-6th-century era. A study by the Shiga Cultural Properties Association describes the present circular mound as about 10 m in diameter and as probably the mausoleum built in 1877. Competing reconstructions place the original mound at roughly 30 m or over 100 m, but the study concludes that its ancient form and size cannot be securely reconstructed. The figure of about 10 m given above is the present mound’s diameter, not an ancient mound length.
Field notes
Worship from the oratory (IHA-managed). Hirohime was a daughter of Prince Okinaga no Mate, so the site can be visited with the Okinaga group of kofun in the Omi area of Maibara, such as Yamatsuteru Shrine Kofun↗, as places linked to the Okinaga clan.