The conversion of ancient monetary units has always been complicated, especially the value of copper coins. According to the Records of Food and Goods in the History of the Song Dynasty, one tael of silver could buy 4 to 8 shi of rice in the Song Dynasty, which is equivalent to approximately RMB 924 to 1848 yuan when converted into modern weight. In the early years of the Song Dynasty, due to the influence of the provincial system, the traditional copper coin, that is, 1,000 Wen or 1 Diaoqian, was once equivalent to 770 copper coins, which is equivalent to 450 to 900 yuan in today's RMB. However, over time, the monetary system changed. In the late Qing Dynasty, the pricing system of "Thirty Wen equals one hundred" even appeared in the Beijing area, which meant that the traditional money was only worth 300 Wen, which is the current RMB 135 to 270 yuan. In ancient China, copper coins were usually circulated in the form of round coins with square holes. A string of coins was threaded with a rope. The original meaning of the word "Guan" is the rope used to thread money. Starting from the Wei, Jin, Southern and Northern Dynasties, the unit of counting copper coins was Wen, and 1,000 Wen equaled the same. However, due to the increase in currency types in the Song Dynasty, the number of articles in Yiguanqian was adjusted to 770. In the Qing Dynasty, there was a saying of "a sling of a thousand yuan, a half of 500 yuan". Finally, in the late Qing Dynasty, the value of Yiguanqian fell to an extremely low level. . Therefore, the actual value of copper coins in ancient times has changed in different dynasties and regions, ranging from 450 to 900 yuan in the Song Dynasty, to only about 135 to 270 yuan in the late Qing Dynasty.