For the first time since the late 19th century, artifacts believed to originate from the Daisen Kofun burial mound, traditionally regarded as the tomb of Emperor Nintoku, have been confirmed and displayed in Japan.

An aerial view of the Daisen Kofun, the tomb of Emperor Nintoku in Sakai, Osaka, Japan (left, Credit: Ministry of Land, Infrastructure, Transport and Tourism) and a detail of Emperor Nintoku from a woodblock print by Toyohara Chikanobu, 1886 (right).

The Daisen Kofun, located in Osaka Prefecture, is the country’s largest ancient keyhole-shaped tumulus and a World Cultural Heritage site. Access to the mound has been тιԍнтly controlled by the Imperial Household Agency, with almost no opportunity for researchers to study the inside. In March, representatives of 17 historical and archaeological organizations were allowed to visit the site with an official escort for the first academic visitation since World War II. They did not enter the tomb, but the event represented a significant opening of access to one of Japan’s most sacred burial sites.

The heightened attention to the tumulus coincided with a sensational revelation. In June, Kokugakuin University Museum announced that it had obtained artifacts from an art dealer a year earlier. After analysis, the museum confirmed that the artifacts were from the Daisen Kofun. They included a ceremonial iron knife with gold-plated copper fittings and silver rivets, and gilded iron armor fragments.

Until now, the only recorded evidence of artifacts from the tomb came from the drawings made in 1872 by Kaichiro Kashiwagi, a local official who investigated the tomb mound after a landslide uncovered part of its chamber. The objects he drew included helmets, armor, swords, and glᴀssware. Most of the items were reburied at the time, but the new evidence shows that not all of them were reburied. The artifacts acquired by the museum had been wrapped in paper dated September 1872, stamped with Kashiwagi’s seal, and labeled as having come from Emperor Nintoku’s tomb.

Some of the discoveries match Kashiwagi’s drawings, such as the armor fragments. Others, like the ornate knife, do not appear in his illustrations, suggesting that Kashiwagi may have privately kept certain objects. The knife, encased in its original Japanese cypress sheath, is unique in its design. Researchers say its use of gold-plated copper sheets and silver rivets has not been seen in other fifth-century grave artifacts.

The Kokugakuin team noted that the objects were not everyday items of use but were produced specifically as grave goods for the emperor. The armor pieces, a few centimeters in size, were found to be iron coated directly with gold. The recent find contrasts with the 19th-century illustrations, which included gold-plated copper, and reveals new evidence of burial craftsmanship in that period.

While other artifacts, including those found in the possession of the Museum of Fine Arts in Boston, were once attributed to the Daisen Kofun, their origins have been debated. The artifacts acquired by Kokugakuin University are the first to be irrevocably confirmed to originate from Emperor Nintoku’s tomb.

More information: Kokugakuin University