This epitaph was accidentally found at the eastern foot of Mt. Ikoma in 1872 during the excavation of earth and sand. The epitaph was engraved on a ruled copper plate (17 letters per column and a total of 173 letters in 11 columns). The first half is about the personal history of the deceased and the second half describes his achievements in a writing style based on the Chinese Book of Filial Piety.
Mino Okamaro was an official in the Nara period who was mentioned as Mino Muraji Okamaro in Shoku Nihongi. According to the inscription, he was granted the name of Muraji from Emperor Tenmu in 684, appointed as a Japanese envoy to the Tang Dynasty in China in 701, granted the rank of Jugoi-ka (official rank) and appointed as the head of Tonomorinotsukasa (an organization in charge of imperial affairs) in 716, passing away on October 20, 728 at the age of 67. This epitaph was created two years later in 730. Although he was appointed as an envoy to Tang Dynasty in China at the age of 40, the details, including the year when he came back to Japan, are unknown. The reason why this epitaph has Chinese characteristics, such as the use of horizontal and longitudinal ruled lines and the writing style based on the Book of Filial Piety, may be related to his background as a Japanese envoy to China.
In 1984, an excavation survey was conducted at the site where this epitaph was found. This time, human bones and charcoal pieces were excavated, showing that the epitaph was buried in a cremation cemetery. This site was designated as a historic site by Nara prefecture. Currently, there is a stone monument in the midst of a residential area, which was built in 1878.