The term "heavenly prison" first appeared in the Spring and Autumn Period and the Warring States Period, which at that time meant that the prison was dark and sunless, and once entered, there was no chance to see the light of day again. Later, it specifically referred to the prison of the imperial court, and was named "Heavenly Prison" to show its majesty. However, there are also different theories, some people say that the "prison" is heavily guarded, and it is difficult to escape or rob the prison; There are also rumors that this kind of national prison is blessed by the "prison god", and this kind of god will take care of the prison, which is the true meaning of "heavenly prison"; There is also a saying that the emperor is the Son of Heaven and is divinely given. The final trial of the cases in the "Heavenly Prison" is judged by the emperor, so this kind of national prison should be called "Heavenly Prison". It means to go straight to heaven and represents absolute justice and majesty. In fact, as long as there is a prison, there will be unjust cases, and there will be unjust ghosts. As long as there is a case, the verdict will be biased, and it will not be 100% just and fair.

The "Heavenly Prison" was not the only one, at least not during the Ming Dynasty. National-level prisons can be called "heavenly prisons", so that there are at least four "heavenly prisons" in the country. The prison of the Criminal Department is one of them, although it has the highest reputation among the people, in fact, its prestige is not very high. Because the authority of this prison is no longer large, it is almost the same as the nature of ordinary local prisons. Another reason is that the prison of the Ministry of Punishment has a bad reputation, causing ordinary people to look down on this national prison.

"Dali Temple" is not a temple, nor is it a Taoist temple, but a state institution. In modern terms, it is the equivalent of today's Inspectorate. However, its rights are somewhat different, and although the officials here have the right to detain and interrogate the current officials, they do not have the power to appoint, dismiss, or make reports. According to the rules of the imperial court, officials below the fifth rank in Beijing and below the seventh rank in the local government are recommended and appointed by the Ministry of Officials. The Ministry of Officials was equivalent to the current Organization Department and the Personnel Department, managing the vast majority of the current officials at that time. Officials with a fifth rank or higher in Beijing and a local rank of seven or more are not the top officials, and they need to be approved by the cabinet and recommended to the emperor, who will be directly appointed by the emperor. It is the Metropolitan Procuratorate that reports and supervises officials, and the Metropolitan Procuratorate is equivalent to the current Commission for Discipline Inspection. Although the "Dali Temple" is controlled by the Ministry of Officials and the Metropolitan Procuratorate, the rights of the "Dali Temple" must not be underestimated. The prison of Dali Temple is dedicated to the detention of suspected officials, although the number is not very large, but it is absolutely qualified to be called "heavenly prison".

Jinyiwei is a feature of the Ming Dynasty, which runs through the entire Ming Dynasty. Whenever later generations mention this brocade guard, they always think of a classic line "Zhu Ming Dynasty brocade clothes in the world". The meaning is obvious, this dynasty is the Ming Dynasty when the Zhu family was the emperor, but it was Jinyiwei who was really in power. Jin Yiwei is the one who really controls the Ming Dynasty. Although this is a bit exaggerated, it is enough to prove the arrogance and power of Jinyiwei. Jinyiwei is divided into the North and South Town Fu Divisions according to their functions, and the functions of the North Town Fu Division are to patrol and supervise various yamen; The function of the Nanzhen Fusi is to detain, interrogate, and dispose of all suspected officials, Shixun, and clan members. Nanzhen Fusi has an independent prison, which is enough to compete with the prison of the Criminal Department and the prison of Dali Temple. However, this prison also has a name called "Imperial Prison", which means that the people detained here are all ordered by the emperor himself, and no one is allowed to intervene without the emperor's direct instructions. For the sake of distinction, and more importantly, for the sake of discrimination against this prison, ordinary people and officials have called it "Southern Prison". Not only did they not recognize this prison as an "edict prison", but they also did not recognize it as a "heavenly prison", and everyone only regarded it as the emperor's private prison.

Compared with the notorious "South Prison", the "black house" of Dongchang is even more scandalous. When it comes to Zhu Yuanzhang, the founding emperor of the Ming Dynasty, I have to admit that he is a character. Whether it is his political enemies, comrades-in-arms, or even bystanders, they have to respect him. His greatest achievement was to overthrow the Yuanmeng Empire, restore the Han family, and re-establish the Han people as the masters of the country. The second achievement was the establishment of a dynasty and army that was quite strong at that time, if it were not for the limited energy, Zhu Yuanzhang might really be able to dominate the world. The third achievement is that for the first time, anti-corruption and clean government have been included in the national policy as a major national matter. Although the prohibition continued, and the more corrupt officials were banned, it gave the future generations of emperors and the imperial court the determination and opportunity to deal with the big corrupt officials. The fourth merit is the "art of checks and balances". "Balance" is not only a strategy, but also a one-and-done approach. Zhu Yuanzhang knows the advantages and disadvantages of his descendants. There will not be a shocking genius in the Zhu family, and there will be no more peerless heroes like Zhu Yuanzhang who is decisive in killing. Because the future emperors of the Zhu family will not have Zhu Yuanzhang's life experience, let alone Zhu Yuanzhang's experience as the Son of Heaven. There is no group of brothers in life and death to escort them, and there is no war orphan who has spent their lives serving their allegiance to take advantage of it. The wise Zhu Yuanzhang invented the art of checks and balances to create a relatively easy path for his future generations of emperors. The six departments manage each yamen, and the local yamen at all levels are responsible for supervising the lower-level yamen, and the supervisor of each level of the yamen is fully responsible. Even the smallest county-level yamen, there is also Zhengbapin County, which contains, Zhengqipinzhi County; The prefect's yamen is controlled by the same knowledge, and the prefect of the five products is contained; The province has assigned political envoys and inspectors to divide power to prevent them from having too much power and making them difficult to manage. In the central cabinet to contain the six ministries, the cabinet is not of high rank, but on behalf of the emperor to check and balance the six departments, the six departments of the book are strictly forbidden to meddle in the affairs of other departments, restricting their authority. Later, the power of the cabinet increased, and in order to prevent the cabinet from having too much power, the Metropolitan Procuratorate was set up to contain it. The Metropolitan Procuratorate not only has the right to "hear and hear", but also has the duty to supervise the cabinet. Once a problem with the cabinet is discovered, the Metropolitan Procuratorate can directly report to the emperor. In order to prevent the authority of the Metropolitan Procuratorate from being excessive, Zhu Yuanzhang issued a strict decree that the officials of the Metropolitan Procuratorate should not only not be too high-grade, but also could not meddle in government affairs, and only had the right to supervise the life style and moral behavior of officials. Use brocade guards to supervise hundreds of officials, and have their own minions to monitor civil and military officials. This is one of Zhu Yuanzhang's achievements. Later, the emperor of the Ming Dynasty found that the power of the Jinyi Guard was still not large enough, and the supervision of officials in the court and China was insufficient, and it needed to be expanded to monitor all walks of life in the country, including the army and border gates. In order to prevent Jinyiwei from deceiving the superiors and subordinates, the emperor announced the establishment of the East Factory to cooperate with and supervise Jinyiwei to monitor the world. Jinyiwei semi-openly supervised hundreds of officials, and Dongchang secretly infiltrated all walks of life among the people, and even disguised themselves as ordinary people as soldiers to monitor the military and army management at the border gates. In order to be able to control Dongchang, the emperor used his cronies and eunuchs to directly control Dongchang, allowed Dongchang to set up prisons independently, and tacitly allowed Dongchang to interrogate and dispose of all suspects independently. No matter how arrogant Jinyiwei's "South Prison" is, it can be regarded as a semi-military imperial court institution, and the prison in Dongchang is simply a lawless place. Therefore, everyone did not even recognize the name of the prison, and directly called it a "black house". But no matter what you call it, this prison is still one of the four "heavenly prisons" of the Ming Dynasty, and it is the darkest one.

If the four "heavenly prisons" are distinguished by size, the prison of the Criminal Department is the largest, the "South Prison" of Jinyiwei is the second largest of the "Imperial Prison", the prison of Dali Temple, also known as the "Official Prison", belongs to the third largest, and the "black house" of Dongchang is the smallest. But in reality, prisons are not consistent in size and reputation, nor are they ranked in terms of efficiency and function. In terms of reputation, the prison of Dali Temple is the first, the Jinyiwei is the second, the Dongchang is the third, and the prison of the Criminal Department is the last. In terms of efficiency, Dongchang is the first, Jinyiwei is second, Dali Temple is third, and the prison of the Criminal Department is at the bottom. Even in terms of prestige and deterrence, Jinyiwei ranks first, Dali Temple ranks second, Dongchang ranks third, and the prison of the Criminal Department is still at the bottom. Why is it that in addition to the largest area occupied by the prison of the Criminal Department, the others are not as good as several other peers? This problem has always plagued laymen and ordinary people, and even the cabinet and the emperor are ignorant of it.

In fact, there are many reasons, including their own reasons, external factors, and objective reasons. First, since the beginning of prisons, there has been darkness and injustice. The occurrence of unjust imprisonment is somewhat unintentional, but it is more because there are people doing tricks and feet in it. Some of these people are officials sitting in the court, and more are clerks below. The officials of the Ming Dynasty were generally not high, and they could not even support their families, and the people below were even more unhappy. Take the head of a prison in the Criminal Department as an example, although he is a member of the government, he has no rank. His annual salary was forty-five taels of silver, and the average was less than seven taels of silver per month. In addition, the money will not be disbursed in full and on time, and the actual amount of money received every year is less than thirty-seven taels of silver. If you only have these incomes, not to mention supporting your family, it is difficult to support him alone. But not only did the cell boss have to feed the two old men in the family, a wife and seven children, but he also had three "outer rooms" outside. Every once in a while, he has to invite guests and beckon his subordinates to go to the restaurant to eat and drink. At the beginning of each month, you have to honor your superiors and masters, at least a thousand taels of silver. Where did he have so much silver? Is it because he is using the family's money to make up for it? No, because he has his own abilities. If outsiders knew that in addition to everything now, this cell boss also had three shops and thousands of acres of fertile land outside the city, they would definitely not believe it. In fact, this is all true, he is just an ordinary cell head in a prison of the Criminal Department. There are hundreds of people like him in the prison of the Criminal Department, and there are thousands of jailers under him.

Second, Jinyiwei and Dongchang took away a lot of authority from the prison of the Criminal Department. Even if the prison of the Criminal Department is not treated as the same, the prison of the Criminal Department has become a slave of Jinyiwei and Dongchang. They beat and scolded the people in the prison of the Criminal Department, and directly drew their knives against each other in the most serious cases, and even killed people like chickens.

Third, there have been too many unjust, false and wrongly decided cases in the prison of the Criminal Department over the years. This has seriously affected the reputation of the prison of the Criminal Department, and the common people and officials have gradually become disillusioned with the prison of the Criminal Department.