The pieces, which belonged to 13 different kinds of mirrors, were the largest number to be excavated as burial items from an ancient tomb in the nation. The tomb dates to between the late third century and early fourth century.
Some of the pieces had been made in the same mold as Sankakubuchi Shinjukyo mirrors, which are engraved with Seishi Gannen (in the Japanese reading), a period name of Wei-dynasty China, meaning the first year of the Seishi era, or 240.
Himiko, a female ruler of the Yamatai-koku kingdom, is said to have received 100 mirrors from the Wei dynasty in that year.
The Kashihara Archeological Institute in Nara Prefecture believes the discovery may help directly link the Yamataikoku kingdom with the Yamato dynasty, in the present-day Kinki region, that was later to be known as the Imperial Court.