In many martial arts film and television dramas, some of the martial arts sects with huge power often have the so-called "forbidden land", for example, Mr. Jin Yong described the Ling Hu Chong of the Huashan Sect in "Smiling Proud of the Rivers and Lakes", that is, in the cave of the forbidden land behind the mountain, a large number of martial arts secret books were found, and thus he knew that Feng Qingyang had to teach the Lone Nine Swords, thus becoming a master of the world.

Generally speaking, these "forbidden places" often have the characteristics of mystery and inadmissibility, and will be marked on the outside with words such as "so-and-so heavy land, trespassers die". Of course, people often think that these so-called forbidden places only exist in novels and film and television works, but in fact, these forbidden places have also existed in real life, such as the Qing Dynasty, there was a very mysterious "forbidden land": the Military Aircraft Department.
The Military Aircraft Department was the center of power in the middle and late Qing Dynasty, so much so that people would refer to the chief military chancellor as the "Prime Minister", that is, the highest-ranking official among the civil and military officials. The establishment of the Military Aircraft Department was closely related to the emperor's own wishes and the situation faced by the imperial court at that time, and the emperor's own will was naturally to firmly grasp the power in his own hands, and the situation in the imperial court at that time gave the emperor this opportunity.
It was in the seventh year of Yongzheng (1729), the Yongzheng Emperor officially sent an army to the Dzungars, the Art of War of Sun Tzu said: "The warriors, the great affairs of the country, the land of death and life, must not be unaware", although the Dzungars are insignificant compared with the Manchu Qing, but this is also a war after all, and the people involved in it need to be extremely cautious and careful, especially the top decision-makers who formulate strategic plans, and they need to keep secrets strictly.
Therefore, the Yongzheng Emperor limited the people involved in the highest decision-making to a very small circle, such as Zhang Tingyu, Ortai and others, who were not only high-ranking and powerful, but also all loyal to their cronies, and designated a small room near the Yongzheng Palace as a duty room, that is, the "military machine room", and these people took Yongzheng as the core and held small meetings behind closed doors.
All policy decisions do not need to be discussed by hundreds of officials, but are directly deliberated by these military ministers, and finally decided by the emperor, and these military ministers themselves have other positions, and the status of this military aircraft minister only allows them to participate in the negotiation and formulation of the highest decision-making process, and does not receive a salary for this, and even the entire military aircraft department can only be regarded as a temporary institution.
More precisely, it is a temporary secretarial institution exclusive to the emperor's individual, and some military ministers are basically equivalent to the emperor's personal secretaries, in fact, this is also the consequence of the continuous concentration of imperial power after Qin Shi Huang created the emperor system, and the emperor needs someone to help him work, so the bureaucratic group represented by "Xiang Quan" has emerged.
However, after the power of this bureaucratic group has increased, it will in turn threaten the imperial power, so the successor emperor will find a way to weaken the power, the basic method is to abandon the original bureaucratic group, and rebuild its own secretarial team, but over time this secretary team also grasps the real power, so it is constantly repeated, such as the Cabinet of the Ming Dynasty and the Military Aircraft Department of the Qing Dynasty.
It is precisely because the Military Aircraft Department was the power center of the Qing Dynasty, and was originally established for foreign wars, so it naturally has confidentiality, from the beginning of its establishment until it was abolished in 1911, there is a ban on "outsiders are not allowed to approach at will, trespassers die", and even the relatives of the Emperor and the State are no exception, which is also easy to understand, if there are Relatives of the Imperial State who trespass on the Military Aircraft Office, then it can basically be determined that he wants to rebel.