楽浪郡
The first known metallic coinage known to have circulated in ancient Korea was Chinese knife money, this type of Chinese coin circulated in the Kingdom of Yan during the Warring States period, and was brought to the Korean peninsula by Chinese settlers and in modern times specimens of knife money have been excavated in the provinces of Pyeongan and Jeolla. During the Chinese Han dynasty Wu Zhu cash coins which were known as "oshujeon" (五銖錢, 오수전) in Korean were brought to the Korean peninsula following the Han conquest of Gojoseon in 108 BC. The "oshujeon" would continue to circulate in the later kingdoms of Goguryeo and Silla of the Korea Three Kingdoms period up to the 10th century CE. Today "oshujeon" are most commonly found in the tombs of the former Lelang Commandery.