Go-Joseon was the first ancient state of Korea and was the earliest ancient state in East Asia, established from the 30th to 24th centuries BC. Dangun, the first king of Go-Joseon, established "Asadar" as the capital. Asadar is assumed to have been set up in Gangdong, situated in the mid-estuary of Daedong river on the Korean peninsula.
As the territory of Go-Joseon expanded, the main capital shifted to the Kaiju area of the Liaodong peninsula in Manchuria around the 20th century BC, along with the establishment of several minor capitals in the region. On the Liaodong peninsula, there still remains some huge, beautiful, table-shaped dolmens that are regarded as the royal tombs of Go-Joseon.
The capital was moved to Kaiju area, and subsequently the Bronze Age metal culture of Go-Joseon was transferred to the Liaodong and Liaoxi region around the 20th century BC. The state attained further maturity in its original region on the Korean peninsula and the adjacent region of Liaodong and Liaoxi of Manchuria, where it spread and developed.
The designs of Bronze Age metal culture of Go-Joseon differ sharply from those of ancient China and Northern Siberia so much so that it is easy to make a clear distinction between them. Mandolin-shaped bronze daggers are considered representative and characteristic examples of the Go-Joseon design.
The mandolin-shaped bronze daggers and some other relics of Go-Joseon metal culture have been found at many places on the Korean peninsula and their discovery at Liaodong and Liaoxi region of Manchuria and In the Chifeng region of Inner Mongolia indicates that they were part of the territorial expanse and cultural zone of the Go-Joseon state. The bronze daggers and the bronze artifacts with thunderbolt pattern are particularly indicative of the territorial zone of Go-Joseon.