This technology also did not present a bottleneck for the goldsmiths of Huaxia. The copperplate paper currency of the Song Dynasty had already used metal movable type to print different anti-forgery identifiers. However, metal movable type never became widespread in the Celestial Empire, rooted in the fundamental differences between the Chinese writing system and the Latin alphabet system.
The Chinese writing system contains over ten thousand characters, with several thousand being commonly used. The Latin alphabet system has only 26 letters, and ancient Latin even had only 21. The scale of type needed for each writing system is entirely different, with a staggering difference of two orders of magnitude. This vast disparity in production costs decides the practicality of the technology.