Please master, briefly describe the characteristics of coins in Song Dynasty.

Coins in the Song Dynasty were generally newly minted every time the year number was changed, and the number and variety of coins were rare in all previous dynasties. During the 300 years of the Song Dynasty, Xiaoping and two-yuan discount were mainly used, and large bills were occasionally used, and their outlines and sizes had certain standards. From the seventh year of the Southern Song Dynasty, Qian Bei began to use numbers to record the years, and his calligraphy style gradually became dominated by the Song Dynasty. Generally speaking, the coins minted in Song Dynasty were very exquisite, especially in Hui Zong period. The first thin golden body was seen in Qian Wen, with exquisite calligraphy and exquisite foundry workers. Fakes are often dwarfed. Another feature of Song Qian is its numerous editions, such as Xuanhe, Zhenghe and * * * with hundreds of editions. There were more than 10 kinds of Jiading iron coins in the Southern Song Dynasty, including Bao Tong, Yuanbao, Chongbao, Xinbao, Yongbao, Zhenbao, Zhenbao, Bao Zheng, Zhibao, Wanbao, etc., and the differences in geographical location, chronological date and chronological value of the stories behind them were original creations since ancient times. Ordinary Song coins cannot be forged, but Kangding, Chongbao Beifang, Guo, Shengsong, Jingkang and other varieties of counterfeit money are more. You must be careful when you encounter such coins, and carefully observe whether there are any forgery marks and whether they are consistent with a large number of ordinary Song coins. There are three styles of money cards in Lin 'an Prefecture in Southern Song Dynasty; One is the upper and lower fillet; The other is the upper and lower corners; The third one is under the upper circle. In the Qing dynasty, counterfeiters used money to turn over sand, and the fakes they made were almost genuine, but the color paste was rusty and inferior, and individual words were out of shape.