National Treasures & Important Cultural Properties
of National Institutes for Cultural Heritage, Japan

This is a seal of an army corps stationed in Onga, Dazaifu. It is 4.2cm by 4.2cm, which is smaller than the legal size of 6cm set by the official codes. Although the four letters of "Ongadan In" carved in relief on the seal surface are in good condition with no wear and tear, the surrounding area is entirely missing. The knob is in the shape of a plectrum without a hole. This was accidentally found on the construction site of the then Kitamikasa Elementary School (currently, Mizuki Elementary School) in 1899. In 1927, another seal similar to this one, on which the letters of "Mikasadan In" were carved, was excavated from a site 800m from this school. Both the Onga and Mikasa seals were created according to almost the same standard, which suggests these were the official seals of the army corps organized under the Ritsuryo (legal codes of the Nara period) system. While it is likely that similar seals were used in other army corps stationed at different places across the nation, there are no other seals except these two that remain.