1. Figure 1 is the copper coin of the Qin Dynasty, when the emperor in power was Qin Shihuang.
2. Figure 2 Five baht coins are copper coins cast by Emperor Wu of the Han Dynasty.
3. Figure 3 Jiaozi is the paper money of Song Dynasty, which was produced in Sichuan at that time.
4. Figure 4 Kaiyuan Bao Tong is a copper coin in the Tang Dynasty. At that time, the emperor who stipulated the unified use of this currency was Emperor Xuanzong of Tang Dynasty.