Kaiyuan Tongbao was the currency of the Tang Dynasty, and coins began to have "Tongbao" in the Tang Dynasty. In the early Tang Dynasty, the Sui Dynasty's five baht was used, which was light, small and mixed. In the fourth year of Wude, Emperor Gaozu of the Tang Dynasty, in order to rectify the chaotic currency system, the Sui Dynasty money was abolished, and the "Kaiyuan Tongbao" was minted to imitate the strict norms of the five baht in the Western Han Dynasty to replace the remaining five baht in society.
The original "Kaiyuan Tongbao" was inscribed by the calligrapher Ouyang Xun, with the inscription "Kaiyuan Tongbao" on the face. The shape still followed the Qin square hole round coin, and it was stipulated that every ten coins weighed one tael, and the weight of each coin was measured. It's one penny, and one thousand penny weighs six catties and four taels.
Extended information:
The "Kaiyuan Tongbao" of the Tang Dynasty ushered in a new era in the history of my country's currency. Since then, bronze coins have bid farewell to the tradition of renaming them after the half-liang and five-baht marks, and have begun to transition toward abstraction and symbolization. "Kaiyuan Tongbao" also established the standard image of Chinese currency in terms of shape and weight. It uses one coin as the legal weight unit, and every ten coins weigh one tael. The decimal system of ten cents and one tael came into being and had a profound impact on later generations.
The four words "Kaiyuan Tongbao" came from Ouyang Xun's handwriting in the early Tang Dynasty. The so-called "Kaiyuan" means opening a new era, while "Tongbao" refers to the universal treasures in a unified country. "Kaiyuan Tongbao" is not a "year name coin". It was minted in July of the fourth year of Wude in the Tang Dynasty (AD 621) - which is nearly a hundred years earlier than the Kaiyuan year of the Tang Dynasty - and was commonly used in the history of the Tang Dynasty for about three hundred years. There has been no interruption, which is also rare in the history of currency.
Baidu Encyclopedia - Kaiyuan Tongbao
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