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Shield-shaped Bronze Mirror and Giant Darkened Sword: Intriguing Finds in Tomiomaruyamamound

Archaeologists from the municipal bureau of cultural properties researched and collaborated in cooperation with the municipal archaeological institute of Kashihara. They have uncovered a giant 2.3-meter-long decorative stone sculpture during excavations at the historical burial mound in Nara City, Japan.

The Tomiomaruyamamound dates from the 4th century AD, during the Kofun Period (AD 300 to 538), representing a pivotal era in Japanese history.

The mound has a diameter of 86 meters and rises to a height of 10 meters, with ongoing excavations uncovering various artifacts such as tools, utensils, classical copperware, bronze ware, and several decorated mirror motifs with god-and-animal motifs.

One of the unexpected discoveries in the mound involves a geometrically decorated disc-shaped object. Excavations have unearthed a giant 2.3-meter-long darkened sword made from iron, along with a shield-shaped bronze mirror in a layer of clay that covers a 5-meter-long wooden coffin.



Typically, bronze mirrors found at archaeological sites in Japan are round, however, the one from the Tomiomaruyamamound is shield-shaped and measures 64 cm in height by 31 cm in width. The back of the mirror is raised, with two rounded patterns that are identical to the typologically inscribed on “Daryukyo” mirrors from the Kofun Period.

Tomiomaruyamamound dates back to the 4th century AD.

According to the researchers, the surface of the shield-shaped bronze mirror is the largest of any known bronze mirror found in Japan, with the only comparable example in size being the bronze mirror discovered at the Hibakaruyarui mounds in Fukuoka.

The sword, measuring approximately 2.3 meters in length, has a slightly bent blade like a snake, a typical example of a “dakoken” sword related to the worship of the snake god. The sword is the largest discovered intact in Japan, and experts suggest that it had a ceremonial purpose to ward off evil.



Recent excavations have revealed a giant 2.3-meter-long oak wood cookware made of iron.

The archaeological experts are yet to open the wood cook, but believe that its contents remain intact as there is no evidence of grave robbing. The team plans to study the cookware at a later date, with the sword and mirror currently undergoing restoration.

Seigo Wada, Director of the Hyogo Prefectural Museum of Archaeology, told Asia & Japan Watch, “I wonder about the status of the person buried with the objects, as the individual was interred with a very unusual sword and mirror. There is a high expectation for the study of the contents of the cook.”