Two molds believed to be among the oldest in Japan discovered at the Yoshinogari ruins in Saga. All of the molds date from the mid-Yayoi period and are believed to are among the oldest in Japan.
One of them is made of amphibole rock, making this the first time a mold made of this stone has been excavated at the ruins. The texture is similar to that of the stone of the Korean Peninsula, which was an advanced area in casting of bronze tools.