After Emperor Qin Shi Huang died in 210 BCE, oppressive taxes and harsh laws ignited widespread rebellion. The next year, Chen Sheng and Wu Guang sparked an uprising, and peasants across the land answered the call. After their deaths, Xiang Yu and Liu Bang led the two main rebel armies against the Qin.
In 207 BCE, Xiang Yu crushed the main Qin army. The next year, Liu Bang led his forces through Hangu Pass into the Guanzhong region, reaching Bashan (east of modern Xi'an), just a few dozen li from the Qin capital Xianyang. By then, the short-reigned Second Emperor Hu Hai had been forced to suicide by the powerful eunuch Zhao Gao, who then installed Hu Hai's nephew Ziying as king. Ziying soon tricked and killed Zhao Gao, wiping out his entire clan. But after only forty-six days on the throne, Ziying surrendered to Liu Bang.
The generals all advised Liu Bang to kill Ziying immediately to avoid future trouble. But Liu Bang disagreed, saying, "The King of Qin has already surrendered; killing him now would lose popular support. The most important thing right now is to win the people's hearts!"
After entering Xianyang, Liu Bang was tempted to settle into the magnificent royal palace, but his trusted advisors Fan Kuai and Zhang Liang cautioned him against it, warning that doing so would cost him the people's support. Recognizing the wisdom in their advice, Liu Bang immediately ordered the palace sealed, leaving only a small guard to protect the palace and its treasury of treasures, before leading his army back to Bashang.
To win the people's support, Liu Bang gathered the elders and local leaders from Guanzhong and solemnly declared, "The harsh laws of the Qin dynasty have caused you all great suffering. That must change. Now I make a pact with you: everyone must follow three simple laws. First, anyone who kills shall be executed."
As soon as the words were spoken, the elders voiced their support: "The first article is well agreed upon—we common folk fear arbitrary killing the most." Liu Bang continued, "The second article: those who harm others shall be punished accordingly." "This article is also well agreed upon—whatever the severity of the injury, the punishment matches the crime." "The third article," Liu Bang went on, "robbery and theft must also be punished accordingly."
The elders strongly supported these three chapters of the agreement. Seeing everyone satisfied, Liu Bang continued, "From now on, we will follow these three chapters of the agreement, and all laws of the Qin dynasty are abolished. Whether officials or commoners, everyone can go about their business and live as usual."
Afterward, Liu Bang dispatched large groups to every county and village to promote the "Three Chapters of the Law." When the people heard this, they were overjoyed and brought out cattle, sheep, wine, and food to reward Liu Bang's army.
By relying on the "Three Chapters of the Law," Liu Bang won the trust, support, and loyalty of the common people.
Later generations used this story, with the phrase "Three Chapters of the Law," to metaphorically refer to setting a few rules through words or writing, or establishing mutually binding agreements.
Source: *Records of the Grand Historian*, Chapter "Annals of Gaozu"
Meaning of the Idiom: Later, the Chinese idiom "约法三章" came to describe metaphorically refer to setting a few rules through words or writing, or establishing mutually binding agreements.