At the close of the Warring States period, Chinese thought was wrestling with a practical question: what could stop centuries of war? Confucians looked for the answer in moral cultivation — if the ruler is virtuous, the people will follow. Han Fei (c. 280–233 BCE), a student of the Confucian Xunzi, rejected that answer and gathered the ideas of his predecessors Shang Yang, Shen Buhai, and Shen Dao into a single system.

It rests on three pillars. Fa (law): rules must be written, published, and without exception — the same measure applies to noble and peasant alike. Shu (technique): the ruler audits officials by matching what they said against what they did; an official is punished for doing less than promised and also for doing more, since both show word and deed out of joint. Shi (position): authority comes from the office, not the character of its holder. The state therefore keeps working even with an ordinary person at its head.

Han Fei's view of human nature is bleak: people calculate their interests, and the ruler's task is not to make them good but to make good conduct pay. Hence reward and punishment — the "two handles" — are government's only real instruments.

The end of the story matches the severity of the thought: his writings impressed the Qin ruler Ying Zheng, but Li Si, his old fellow student at the Qin court, had him imprisoned and forced to drink poison in 233 BCE. Eight years later Ying Zheng unified China as Qin Shi Huang and built the empire along the very lines Han Fei had described. The Qin dynasty lasted fifteen years; the Han dynasty that followed formally condemned Legalism while keeping its institutions. That tension — a Confucian vocabulary over a Legalist skeleton — ran through the Chinese imperial state for two thousand years.