Wu Zhu (Zhu is without the Jin component), outer rim / Inner rim only. 18mm, 1.22 grams. Gratzer/Fishman #B7.1 

The Jin dynasty is usually divided into the Western Jin (265-316) and Eastern Jin (317-420). The break occurred when the civil wars and the barbarian invasions of the Wu Hu confederation from the north forced the Western Jin Emperors to escape capital in Luoyang (311) and move it to Chang'an. However, Chang’an had to be abandoned within a few years (316). Sima Rui, a member of the royal family, escaped south and founded the new “Eastern Jin” dynasty in Jiankang (modern Nanjing) in 317.

Unconditionally guaranteed to be authentic.