North Korea has excavated four more metal type pieces from the palace site of the ancient Koryo dynasty in Kaesong, Pyongyang’s Korean Central News Agency (KCNA) reported on Wednesday.

The two Koreas have conducted a number of joint excavation projects in recent yeas but the North conducted this one autonomously, as every inter-Korean exchange project, including humanitarian aid, has been suspended since Pyongyang’s nuclear test early this year.

“Three of the metal types are of cuboid shape, 12-13mm wide, 10-11mm long and 6-7mm high … The last type is 7mm wide and 6mm long,” the KCNA article reads.

North Korean historians