According to textual research by many experts on tombs in the early Tang Dynasty, the issue of Kaiyuan staging can be divided into the following periods: in the fifth year of Huichang (AD 845), Tang Wuzong destroyed the Buddha, and the copper material obtained from the destruction was cast into Huichang Kaiyuan, with a diameter as large as that of the previous Kaiyuan, and the name of the country was cast on the back, such as the word "Jing" and the word "Chang" in Yangzhou. There are obvious differences in the process of casting money from place to place, most of them are skewed, the casting text is vague, and some of them appear flower-piercing phenomenon. A year later, due to the death of Tang Wuzong, Huichang Kaiyuan stopped casting. Both of them are Huichang Kaiyuan, with obvious differences in quality, and there may be differences between official casting and private casting. In numerology, Huichang Kaiyuan is generally considered as a typical specimen of Kaiyuan in the late Tang Dynasty. Huichang Kaiyuan includes Jing (Chang 'an, Jin 'an), Chang (Yangzhou), Luo (Luoyang), Yi (Chengdu), Jing (Jiangling, now Jingzhou), Xiang (Xiangyang), Lan (Lantian), Yue (Yuezhou, now Shaoxing), Xuan (Xuancheng) and Hong (Hongzhou, now Nanchang). Hanzhong), Guang (Guangzhou), Zi (Zizhou, now Santai), Fu (Fuzhou), Gui (Guiyang, now Chenzhou), Dan (Danzhou, now Yichuan) and Yong (Yongzhou) ***23 Signboards of the Bureau of Land and Finance.

Pupin Kaiyuan casting in the late Tang Dynasty followed the characteristics of Kaiyuan in the middle Tang Dynasty after the Anshi Rebellion, and there were many small moon marks, moon marks, many moon marks or turning back to Kaiyuan. This Kaiyuan copper is black, with high iron content and illegible handwriting. Qian Wen's strokes are slender, and the first three strokes of the word "Tong" are stacked continuously, or seem to be disconnected. Most of them have irregular outlines, and some were privately cast in the middle and late Tang Dynasty. As for the spread of flowers, experts verified that it was cast in the middle Tang Dynasty, mainly in the late Tang Dynasty. The word "Kai" in Huachuan and Guizhou develops to a wide style, with the prefix "Yuan" horizontally lengthened, the shape of "Tong" slender, the first three strokes of "Lian" twisted continuously, the stroke of "Bao" slender, the inner side of "Bei" horizontally elongated, and the left and right vertical strokes connected, with a diameter of 23 mm to 24 mm. The copper is impure and the casting workers are sloppy and numerous.

Refers to Kaiyuan coins with a diameter of 265,438+0 mm to 23 mm These small Kaiyuan coins may have been privately cast by the people in various periods. The Book of the Old Tang Dynasty and the Record of Food Goods wrote: "Apart from official casting, there are many private casting". Experts according to the excavation unearthed specimens of small kaiyuan, according to its popular stage, roughly divided into three types:

First, Qian Wen's handwriting imitates Wude Kaiyuan as much as possible, but the money is only 23mm in diameter and weighs less than 3g. Qian Wen is still clear, the outline is still regular, and the copper is not very bad; Type ⅱ, small kaiyuan in the middle Tang Dynasty, with vague fonts, rough casting process, copper doped with iron and lead, and serious corrosion; Type III, small kaiyuan in the late Tang Dynasty, with different widths, black copper, iron and lead, thin meat, fuzzy mold, nearly flat money back, diameter of 22 mm to 23 mm, weight of 1.7g to 3 g, mostly privately cast. 1, June, 907 (April 18, God bless Tang Aidi), the Tang Dynasty perished, and the history of China entered the Five Dynasties and Ten Kingdoms period. Among them, Fujian, Chu, Southern Han, Southern Tang and other regimes have successively cast Kaiyuan Bao Tong. Except for the characteristics of Kaiyuan Bao Tong in the Southern Tang Dynasty, other forms are different from those in the Tang Dynasty. Among them, Fujian Kaiyuan font is vigorous, followed by "Min", "Fu" and "Yin", which was once mistaken for Huichang Kaiyuan. Bao Tong in Kaiyuan of Han Dynasty in southern Chu is made of Xiaoping lead, which is light in currency, rough in workmanship, obscure in words and diverse in words. However, due to a small amount of casting, the market price is high. During the Southern Tang Dynasty, Kaiyuan Bao Tong basically continued and developed the characteristics of the Middle Tang Dynasty, and created a number of coins with the same characteristics except different fonts. There are two kinds of seal script and official script in Kaiyuan Bao Tong in the Southern Tang Dynasty, among which official script basically follows the Tang system, and both seal script and official script are exquisite in workmanship. They are the most exquisite coins of the Five Dynasties. In the early period, the currency was wider, and in the later period, due to the decline of national strength in the southern Tang Dynasty, the currency was lighter than in the early period. Bao Tong in the Southern Tang Dynasty was slightly more expensive than that in the Tang Dynasty because of its large casting volume and low price. In addition, there are four patterns on the back of Kaiyuan Bao Tong in Southern Tang Dynasty, which are more expensive.

In the eighth year of Song Taizu Kaibao (AD 975), the Southern Tang Dynasty destroyed the Song Dynasty. Due to the popularity of Bao Tong in the Song Dynasty, the official casting of Kaiyuan Bao Tong stopped and withdrew from the circulation stage, but there were still folk casting until the end of the Qing Dynasty, mainly for fear of winning the prize.