In ancient times, half a jin was as much as eight liang. In ancient times, one jin was sixteen liang, so half a jin was eight liang. However, after liberation, eight liang was a little more than half a jin, because the State Council issued the Order on the Unified Measurement System on June 25, 1959, retaining the city system. "The city system was originally set to be sixteen liang for one jin, and should be changed to ten liang for one jin".
The term "half a jin, eight liang" comes from the popular period of the ancient weighing instrument in hexadecimal system. Since the ancient term "one jin" was 16 liang (used until the 1950s), there is no difference between "half a jin" and "eight liang".
After Qin Shihuang unified the six states, each of them has formed its own characters and weights and measures due to the division of the states for hundreds of years. After the unification of the First Emperor of Qin, he found that the weights and measures of the whole country were not unified, which made the life of the residents extremely inconvenient. So the First Emperor of Qin issued an imperial edict to require Li Si to formulate weights and measures.
In fact, the unification of weights and measures is a very complicated process. After Li Si's investigation, the system of weights and measures is based on baht, liang, jin, jun and shi. Twenty four baht is one or two, sixteen liang is one jin, thirty jin is one jun, and four jun is one stone. In this way, the sixteen liang scale has been used before liberation.