Different casting processes, different sizes and thicknesses of molds are also important points to distinguish the top ten copper plates. In the Qing Dynasty, ten copper rings were generally smooth-edged, but there were also a few ten copper rings cast by provincial bureaus with toothed edges. There are also a few provincial bureaus that have cast ten copper rings that are larger or thicker than the regular ones.
At the end of the Qing Dynasty, the central government clearly stipulated that the materials for casting copper rings were 97%-98.3% copper, 2-3% zinc, tin 1% and others. This copper content is a common version. At that time, the official edition contained 75%-85% copper, and most of the ten copper rings cast by the provincial bureau were qualified copper rings. Moreover, most of the ten copper rings cast by the provincial bureau are red copper rings that meet the requirements, but some provincial bureaus still cast brass rings with only 70% copper content.
Among the ten existing copper rings, copper rings cast in Sichuan, Fengtian, Hunan, Hubei, Zhejiang, Jiangxi, Beiyang, Shandong, Henan and Fujian provinces were found. Among them, most of the ten copper rings made in Fengtian are brass, and few are red copper. There are relatively many brass rings made in Sichuan, Hunan and Zhejiang, and it is not difficult to find them. The bronze cast by other provincial bureaus is ten copper rings, which are extremely rare in the world. Now it can be met but not sought.