Wu Zhu / Blank. 25mm, 1.81 grams. Hartill/Fishman "One Thousand Years of Wu Zhu Coinage" #4.347.

Rated "very rare" in Gratzer/Fishman.

These coins were cast from filed coins of old types. Their mother coins were Western Han Wu Zhus carefully filed with a partially removed outer rim and an enlarged hole. They are relatively easy to identify because they are cruder, which is expected given that they used previously circulated coins as mother coins, considerably lighter, and they have a large hole. These privately cast coins circulated in the middle and later Eastern Han period based on the archaeological data, though their precise dating is impossible at this time.