| Location | Osaka Pref. |
|---|---|
| Shape | Keyhole-shaped mound |
| Mound length | 226 m |
| Period | Mid 5th c. |
| IHA designation | IHA-managed (no public entry) |
226m in total length, ranking 21st largest nationally. The rear circle is ~135m in diameter and ~17m high; the front section is ~124m wide and ~17m high. A large keyhole mound with a surrounding moat, well preserved overall. Designated by the IHA as Emperor Keitai's mausoleum, but the archaeological date (mid-5th century) predates the emperor's death in 531 CE by approximately 70–80 years, fueling an ongoing identification dispute. It stands on a ridge in the Mishima (Settsu) region with a commanding view over the Yodo River corridor.The debate over whether this or Imashiroduka is the true tomb of Emperor Keitai remains unresolved. The IHA's attribution is based on historical geography studies of the Edo–Meiji period, predating modern archaeological dating methods. It was selected as the site of the "Aino-no-Misasagi" recorded in the Nihon Shoki and Kojiki, but the dating discrepancy has led most modern scholars to favor Imashiroduka. Without IHA permission for excavation, a definitive answer is unlikely. The contrast with Imashiroduka—a fully accessible public park and national historic site open to scholarly research—is stark. Emperor Keitai himself is a pivotal figure: summoned from distant Echizen (Fukui Prefecture) to restore the royal line, he embodies the regional expansion of early Japanese kingship, making the location of his true tomb a matter of fundamental importance to ancient history.
IHA-designated mausoleum (Mishima-Aino-no-Misasagi); entry and excavation are prohibited. From exterior observation, haniwa (cylindrical and figural types consistent with mid-5th-century typology) have been reported scattered around the perimeter. These haniwa types are compared with finds from Imashiroduka Kofun (Takatsuki City, same period) in scholarly debates over the mound's date relative to Emperor Keitai's reign. Interior burial chamber and grave goods remain unknown. Archaeological consensus currently favors Imashiroduka as the actual Keitai tomb; excavation of this mound could potentially yield decisive evidence.