What spy agencies were there in ancient China?

There is little information that the organization of the West Factory can tell, because this is a temporary product, because it has only been established for five years. At the beginning, in order to strengthen the spy rule, Ming Xianzong added the West Factory outside the East Factory, called it the Factory Guard together with the East Factory and the Royal Guards, and used eunuch Wang Zhi as the prefect. His influence surpassed that of the East Factory, and his activities ranged from Beijing to all parts of the country.

Because the secret service agencies of the Ming Dynasty had already established the Royal Guards and the East Factory, it was really unnecessary to set up the West Factory, and its authority exceeded that of the East Factory, which also led to the dissatisfaction of the people in the East Factory. Finally, due to opposition, it was forced to cancel. In the first year, Zheng De briefly reopened for five years, and then it was revoked. The West Factory directly obeyed the emperor and was not controlled by any other organization or individual. As a short-lived secret service, there were only two prefects in Xichang, namely Wang Zhi and Gu Dayong.

I believe everyone is familiar with the organization of the East Factory. It can be said that the Royal Guards coexist. Although it was founded in the period of Judy, the founding emperor of the Ming Dynasty, it can be said that it was dedicated to suppressing the Royal Guards, because its authority was higher than that of the Royal Guards. It is a privileged supervision organization, secret service and secret police agency in Ming Dynasty, and also the earliest national secret service intelligence agency established in world history.

The difference of Black Royal Guards in this institution is that it is directly controlled by eunuchs. When Judy seized the world, the eunuchs around him risked their lives and won Judy's trust. One of the most famous eunuchs is Zheng He, who went to the Western Ocean seven times. Another important reason for the establishment of the East Factory is that Judy robbed his nephew of the throne and became suspicious of the former Royal Guards, which was directly responsible to the emperor. Therefore, the East Factory is allowed to monitor the Royal Guards, and at the same time monitor the assassination of people who are unfavorable to the people. Factory employees are usually composed of ferocious elements and lawless elements in the Royal Guards. They can collect information anywhere, including state agencies, and they are the confidants of the court.