In the early Han Dynasty, the Qin system used half-liang coins, about 12 baht (one tael is 24 baht).

During the reign of Emperor Wu of the Han Dynasty, the five-baht coin was designated as a copper coin weighing five baht.

During the Tang Dynasty, Li Yuan made Kaiyuan Tongbao (not the Kaiyuan name of Li Longji's Kaiyuan year), which was eight cents in diameter and weighed two baht. Ten coins were worth one tael, and a thousand coins weighed six catties and four taels.

Because a pound in the Tang Dynasty was more than twice as heavy as a pound in the Western Han Dynasty, Kaiyuan Tongbao is slightly heavier than the five-baht coin in the Western Han Dynasty