Two Chinese characters Wu Zhu (=5 Zhu), no rims / Blank, inner rim only. 18mm, 1.16 grams. Schjöth #306; Hartill 10.28.
"Zha Bian Wu Zhu" means "Chiselled rim Wu Zhu" - these coins are the older Wu Zhus (both the Western Han and the Eastern Han issues) with the outside cut off to make extra profit of the clipped edges. Some coins were actually cast without the outside rim. The widespread clipping probably took place in the troubled "Southern and Northern Dynasties" period all over ancient China.
The Southern and Northern Dynasties (420-589 AD) was a period in the history of China, following the Jin Dynasty (265-420) and followed by the Sui Dynasty. It was an age of civil war and political disunity. However it was also a time of flourishing in the arts and culture, advancement in technology, and the spread of foreign Mahayana Buddhism and native Daoism. Distinctive Chinese Buddhism was also matured during this time and shaped by the northern and southern dynasties alike. The establishment of the Sui Dynasty and the invasion of the south reunified the whole of China by the end of the 6th century AD. This coin is unconditionally guaranteed to be authentic