The proportion of silver and copper coins is uncertain, which is 1884 (the tenth year of Guangxu), 1: 2400, 1896 (the twenty-second year of Guangxu), 1: 2000, with an average of around 1: 2200 per year.

In addition, not all Qian Wen on copper coins are titles, and title money became popular only after the Northern Song Dynasty.

In the Qin and Han Dynasties, Qian Wen was like two halves, and five baht was a symbol of weight.

There was no Bao Tong's money in the Kaiyuan period of the Tang Dynasty. Although the year of Xuanzong in the Tang Dynasty was Kaiyuan (7 13-74 1), Kaiyuan Bao Tong was first cast in Wude, Tang Gaozu (62 1), and later in Gaozong, Wuhou and Xuanzong periods, which became the standard copper coins in the Tang Dynasty. Later, during the Southern Tang Dynasty and the Five Dynasties and Ten Kingdoms Period in Fujian, Kaiyuan Bao Tong was also cast.

In addition, there are some non-year numbers of Qian Wen in the Song Dynasty, such as Bao Tong in the Song Dynasty and Bao Tong in the Song Dynasty, which are auspicious words. After the Song Dynasty, copper coins were basically titles, especially in the Ming and Qing Dynasties. Because in the Ming and Qing Dynasties, the emperor basically had only one title, so Qian Wen was a title.