About 200 years ago, Dasan Jeong Yak-yong said that people who cannot express their grievances are like sick children who cannot properly express where they are hurting.
That is why the officials believed that they should listen to the people's appeals with the same heart that parents treat their children.
Here we can see that Dasan's mind overlaps with that of King Sejong.
The great king solved the suffering of the people who ‘had something to say but could not properly convey their intentions’ by creating Hunminjeongeum.
And about 400 years later, Dasan left behind a book of criminal law for the people who could not properly resolve their grievances through lawsuits, and that was “Heumheumsinseo.”
This book examines the great visionary Dasan's "Heumheumsinseo" and attempts to organize various episodes about the model of a just country and justice that Dasan dreamed of.
In these times when justice is blurred and money reigns supreme, we can reflect on the wisdom needed to create a fair society.

In Dasan's eyes, the people who could not express their grievances were like sick children who could not properly express what was wrong.
He listed three reasons why people could not resolve their grievances through litigation. The first reason was that fists were closer than the law.
“Even when villagers want to appeal their grievances, they are often afraid to raise the issue publicly for fear of incurring the wrath of powerful officials or wicked local officials.
Because of this, the people speak vaguely and their words always sound incoherent, which is the first reason why people keep silent even when they are wronged.”
Dasan, who likened the people who dare not speak out about their suffering and grievances because of those in power to children who cannot speak, believed that the people's appeals should be listened to with the same heart a parent would give to their children.
---Chapter 1: The Duties and Attitude of the Shepherd

Dasan criticized Joseon's law enforcement for failing to realize justice by prioritizing forgiveness and tolerance or failing to accurately investigate cases, thereby not punishing those who deserved punishment.
Of course, this does not mean that Dasan was obsessed with severe punishment or trying to hold people responsible for their suicide.
He emphasized that truly just politics is only possible when a case is first investigated accurately and objectively, and then strict punishments and leniency are appropriately administered.
---Chapter 6: Accurate Investigation of the Case is Essential

“Since the case involves human life, we must do our best to make a judgment.
Recently, people have been deluded by the idea that they should do good deeds, and have become caught up in vulgar customs such as releasing the guilty.
These people do not consider the fact that their wrong judgments have caused resentment among good people, and this is the worst thing that can happen, and we cannot help but be wary of it.
Of course, there are cases where we should just let it go out of pity for a person, but if a person has committed an unforgivable crime, we must judge them with justice.” ---「Chapter 13 The law must be accurate and precise」

The person who was most concerned about the spread of private revenge in the late Joseon Dynasty was Dasan Jeong Yak-yong.
He repeatedly emphasized public punishment by the state instead of private revenge.
However, we should not misunderstand that Dasan only recognized public punishment by the state and prohibited all private revenge.
Dasan emphasized that if multiple conditions are met, this should be allowed so as not to damage the ethics and moral foundations of Confucian society.
He believed that excessive private violence endangers society, but just violence can make society healthy.
It is not right to kill others without permission, but if it is a just act of violence, such as avenging one's father, then there is no problem.
This is the core of Dasan's theory of revenge.
---Chapter 17 Conditions for Revenge

What judgment did King Yeongjo make about his son, Crown Prince Sado's madness? In truth, finding a father who would kill his son is as difficult as picking a star from the sky.
What this means is that virtually no father would respond in the same way even if his son tried to kill him.
The same was true for King Yeongjo, who seems to have hoped that the exiled prisoner would reflect on his actions after he sentenced Crown Prince Sado to exile.
Anyway, the Crown Prince died while locked in a chest.
Despite King Yeongjo's regret, this incident complicated subsequent political history.
King Jeongjo believed that although Crown Prince Sado had shown signs of madness and caused many problems, he was not worthy of death.
In other words, he thought that some of the Noron faction had incited King Yeongjo to kill Crown Prince Sado.
Because of this, King Jeongjo, who ascended to the throne, was forced to hold some people from the Noron Byeokpa faction responsible for the death of Crown Prince Sado.
---Chapter 30: Punishment of the Mad

In the late Joseon Dynasty, many people claimed that they were eligible for reduced sentences.
They were the ones who claimed it was negligence even though they killed someone intentionally, those who claimed it was madness even though they were not crazy and escaped punishment, and those who claimed it was justice even though they killed someone.
But the ones who caused the most serious problems were the local nobles and the royal relatives.
In Dasan's view, the tyranny of the local aristocrats during the Joseon Dynasty was excessive.
(Omitted) If it is difficult to completely exclude privileges, the ‘privileged class’ to which exceptions can be applied must be very narrowly defined.
Dasan believed that it was important to prevent anyone from claiming or demanding privileges, which is why he argued for 'exceptions to the application of the law'.

---Chapter 31: Mencius Was Wrong