[1][page needed] In one of the stories, a prince who was running low on money to pay his troops allowed them to use their knives as a form of currency to barter with villagers, and the medium became so popular that it became generally accepted.

In another story, the same prince began accepting knives as payment for small fines in place of the current legal ring money.

[3][self-published source] Qi knives can be categorised based on the number of Chinese characters are present on the obverse side of the knife.

[9] This is the first known commemorative coin in the history of China and its inscription is written in an ancient Chinese script which today has become difficult to decipher.

[9] The inscription is believed to be "qi zao bang chang fa huo" (simplified Chinese: 齐造邦长法化; traditional Chinese: 齊造邦長法化; pinyin: qí zào bāng cháng fǎ huà) which translates into English as "Qi, establish state long, legal money".

[9] Professor Song Jie (宋杰; 宋傑; sòng jié) wrote in an academic paper entitled "A History of China’s Ancient Money" (中国古代货币史; 中國古代貨幣史; zhōng guó gǔ dài huò bì shǐ) about the contemporary purchasing power of a Qi knife.

[9] During the late Warring States period, one dou (斗) of rice, equivalent to about 10 litres, could be purchased with 3 Ban Liang cash coins.

[9] The Six Character Knives (六字刀) issued by the State of Qi were the first Chinese form of money to commemorate the founding of a new ruling family or dynasty (開國紀念幣).

[16] In his attempt to restore the ancient institutions of the Zhou dynasty, Wang Mang had issued many different types of money in very many forms.

[17][16] Because of the unrealistically high nominal value of the money issued under Wang Mang, many Chinese people had turned to casting their own coinages as a response, in order to minimise their losses.

[16] As a countermeasure, however, Wang Mang issued edicts that stipulated very strict punishments for those who were caught privately casting coins during his reign.