Wu Zhu, inner rim only on the right side of the hole, head of Jin tilting right, stout outer rim / Inner and outer rims. 23mm, 2.69 grams. Hartill 10.26; Gratzer/Fishman "One Thousand Years of Wu Zhu Coinage" #9.5. 

The Sui dynasty was a short but highly important Chinese dynasty that ruled from 581 to 618 AD and reunified China after centuries of division following the fall of the Han dynasty. Founded by Emperor Wen, the Sui centralized government power, reformed taxation and administration, and began major construction projects, most famously the Grand Canal, which linked northern and southern China. The dynasty also strengthened the Great Wall and promoted Buddhism. However, massive public works projects, heavy taxation, and costly military campaigns against Korea exhausted the population and led to widespread rebellions. The Sui collapsed in 618 AD and was succeeded by the far more enduring Tang dynasty, which inherited many of its reforms and institutions.