This artifact is made of jade. The main production sites of quality jade in Japan are the basins of the Hime River and Omi River in the southwestern part of Niigata. It is known that the ore drifts ashore at Itoigawa, Niigata and Asahi-machi, Toyama. In these areas, many ruins of jade production sites have been found, from which jade ore of the middle Jomon period, their flakes including residues, unfinished items and tools for processing have been excavated. This artifact may have been brought into this area as a finished product from a certain production site or manufacturing ruins.
This artifact in the shape of an axe is well polished and has a hole in the upper part. Since so-called Kogyokusei Taishu (literally big gem made of jade) including this one have been excavated along with human bones, it is assumed that these gems were used as ornaments hung on the chest. Since most of the Kogyokusei Taishu are in the shape of a dried bonito, this one in the shape of an axe is very rare.