OSAKA - A previously unidentified landform believed to be a "square earthen platform" has been discovered in the front section of the Daisen Kofun in Sakai, Osaka Prefecture, the Imperial Household Agency revealed on May 17th, raising the possibility that the structure may have been used as a burial facility.
The Daisen Kofun, managed by the Imperial Household Agency as the mausoleum of Emperor Nintoku, is Japan’s largest keyhole-shaped burial mound. Built in the 5th century, the tumulus measures approximately 486 meters in length.
The newly identified feature was confirmed through analysis of the burial mound using a "red relief image map," a visualization technique that allows subtle terrain details to be examined more clearly. According to the agency, the structure appears to be a "square earthen platform" formed by piled soil in the mound’s front section.
The discovery could provide new clues about the construction and burial practices associated with the massive kofun-era tomb, although the Imperial Household Agency has not yet determined the exact nature or purpose of the landform.
Emperor Nintoku is traditionally regarded as the 16th emperor of Japan and is believed to have ruled during the 4th and early 5th centuries, although the exact dates of his reign remain uncertain due to the semi-legendary nature of Japan’s early imperial history.
Known in Japanese as Nintoku Tenno, he is remembered in historical chronicles such as the Nihon Shoki and Kojiki as a benevolent ruler who cared deeply for the welfare of his people. One of the most famous legends associated with Nintoku tells of the emperor climbing a hill and noticing very little smoke rising from homes, leading him to conclude that the people were suffering from poverty. According to the story, he suspended taxation and labor duties for several years to help the population recover.
The Daisen Kofun in Sakai, Osaka Prefecture, which the Imperial Household Agency manages as his mausoleum, is considered the largest keyhole-shaped burial mound in Japan and one of the largest tombs in the world. Constructed in the 5th century, the massive tomb stretches about 486 meters in length and is surrounded by multiple moats and densely wooded grounds.
The burial mound is part of the Mozu-Furuichi Kofun Group, a cluster of ancient tombs that was designated a UNESCO World Heritage site in 2019. Archaeologists and historians regard the kofun as an important symbol of the political power and advanced engineering capabilities of Japan’s early ruling elite during the Kofun period.
Source: Kyodo
