The earliest Fu Jie with documents to test is the tooth Zhang made by Zhou instead of jade. There is such a record in "Zhou Li Chun Guan Dian Rui": "Ya Zhang takes a military salute and guards the soldiers." Zheng Sijia's note: "Send troops with teeth, if you send troops with bronze symbols today." Later, the charm was no longer made of jade, but was generally made of copper, with relevant words written on it, which was split into two parts, one for the court and the war generals. When the imperial court needs to mobilize troops, the emissary must go with a symbol to show his true identity, and the general will accept the command to transfer troops only when he is verified by the "combined symbol". Because most of these military symbols are made in the shape of tigers, they are also called "tiger symbols". The new Hu Fu symbol discovered by archaeology is a bronze military symbol of Qin State in the late Warring States Period, and it is inscribed with the following words:

The symbol of an armored soldier, the right belongs to the king, and the left belongs to Xin Fu (place name, Wei land newly captured by Qin). Anyone who is (the same as "wearing") armor and uses more than 5 soldiers will certainly know Wang Fu and dare to do it. Although you don't know how to behave, you will be beaten.

This inscription clearly states that anyone who transfers more than 5 soldiers must use the military symbol as a voucher, and anyone who does not meet the requirements cannot send troops. It can be seen that the military symbol, as a token of the transfer of troops, occupied a very important position in the military activities at that time.

in addition to the tiger symbols used between the monarch and the generals, there are also symbols between the upper and lower levels in the army. "Mozi's Order" contains: "The general will make people guard and operate the letter. If the letter does not correspond to the number, Bo Chang (that is, the centurion, the grass-roots official in the army) will stop it in order to hear about the general. " This kind of symbol can't be seen in kind now. Because there is a saying in Zhuangzi that "the symbol is burned and the seal is broken", it is estimated that it should be made of bamboo.