Imperial Household Agency: Mishima-no-Aino-no-Misasagi (Mausoleum of Emperor Keitai)
Location
Ibaraki, Osaka
Shape
Keyhole-shaped mound
Mound length
226 m
Period
Mid-5th c.
Designation
IHA-managed tomb
IHA designation
Managed by the IHA (mound closed to the public)
Overview
A 226m-long keyhole mound in Oda, Ibaraki, and the largest in the Mishima region. It is dated to the 5th century. The Imperial Household Agency designates it as Emperor Keitai's Mishima no Aino mausoleum, but the construction date does not align with Keitai's lifetime, so its archaeological occupant is unresolved.
Finds & research
Because it is administered as an imperial mausoleum, details of the burial facility and grave goods remain unknown.
Official status & archaeological view
Official status
The Imperial Household Agency administers the mound as Emperor Keitai's Mishima no Aino mausoleum. It is in Oda 3-chome, Ibaraki, and the Agency records its form as keyhole-shaped.
Attribution (jitei): the Imperial Household Agency's determination of whose tomb it manages — separate from heritage designation.
Archaeological view
Takatsuki City dates Oda Chausuyama to the mid-5th century and regards Imashirozuka as the true tomb of Great King Keitai, who died in 531. Ibaraki City's public newsletter says the prevailing view today is that Oda Chausuyama is not Keitai's mausoleum; its occupant remains unidentified.
Field notes
The mound is closed to general entry. Per the IHA, it is about a 4-minute walk from the Oda 3-chome bus stop, and worship is generally possible year-round from 8:30 to 17:00. The goryoin (mausoleum seal) is kept at the Momoyama Mausolea Office in Fushimi-ku, Kyoto, where visitors can use it free of charge (reception 8:30–17:00; staff may be unavailable on weekends, holidays, 29 Dec–3 Jan and some other days).