Li Si in the context of "Legalism (Chinese philosophy)"

The Hundred Schools of Thought (Chinese: 諸子百家) were philosophies and schools that flourished during the late Spring and Autumn period and Warring States period (c. 500 – 221 BC). The term was not used to describe these different philosophies until Confucianism, Mohism, and Legalism were created. The era in which they flourished was one of turbulence in China, fraught with chaos and mass militarization, but where Chinese philosophy was developed and patronized by competing bureaucracies. This phenomenon has been called the Contention of a Hundred Schools of Thought.

The philosophies that emerged during this period have profoundly influenced East Asian culture and societies. The intellectual landscape of this era was characterized by itinerant scholars, who were often employed by various state rulers as advisers on the way of government, war, and diplomacy. Often, members and traditions of the same school had little in common other than the same influential figure that their beliefs were based on. This period ended with the rise of the imperial Qin dynasty and the subsequent burning of books and burying of scholars as part of an ideological suppression effort by Qin Shi Huang and Li Si.

Fa is a concept in Chinese philosophy that concerns aspects of ethics, logic, and law. Although it can be accurately translated as 'law' in some contexts, especially modern Chinese, it refers to a 'model' or 'standard' for the performance of behavior in most ancient texts, namely the Mozi, with a prominent example including the performance of carpentry. Although theoretically earlier, Fa comes to prominence in the Mohist school of thought. An administrative use of fa standards is prominently elaborated in Legalism, but the school of names also used fa (models) for litigation. Given its broadness, the term fa even included medical models (theories).

Fa was still considered important by Warring States period Confucians. Xunzi, whose work would ultimately be foundational to Confucian philosophy during the Han dynasty, took up fa, suggesting that standards could only be properly assessed by the Confucian sage (聖; shèng), and that the most important fa were the very rituals that Mozi had ridiculed for their ostentatious waste and lack of benefit for the people at large.

Xunzi (荀子, Xúnzǐ, lit. 'Master Xun'; c. 310 – c. after 238 BCE), born Xun Kuang, was a Chinese philosopher of Confucianism during the late Warring States period. After his predecessors Confucius and Mencius, Xunzi is often ranked as the third great Confucian philosopher of antiquity. By his time, Confucianism had suffered considerable criticism from Taoist and Mohist thinkers, and Xunzi is traditionally regarded as a synthesizer of these traditions with earlier Confucian thought. The result was a thorough and cohesive revision of Confucianism, which was crucial to the philosophy's ability to flourish in the Han dynasty and throughout the later history of East Asia. His works were compiled in the eponymous Xunzi, and survive in excellent condition. Unlike other ancient compilations, his authorship of these texts is generally secure, though it is likely that Western Han dynasty historian Liu Xiang organized them into their present form centuries after Xunzi's death.

Born in the state of Zhao, Xunzi studied at the prestigious Jixia Academy, where he learned about every major philosophical tradition of his time. After his graduation, Xunzi traveled to Chu where he mastered poetry, and then returned to Qi as a highly regarded teacher at the academy. His students Han Fei and Li Si each had important political and academic careers, though some of their Legalist sentiments were at odds with his philosophy. Other students such as Fuqiu Bo [zh], Zhang Cang and Mao Heng [zh] authored important editions and commentaries on the Confucian classics. Later in his life, Xunzi served in the court of Lord Chunshen and died sometime after Lord Chunshen's death. The constant warfare of his time informed his work profoundly, as did his interactions with leaders and witnessing the downfall of various states.

Qin Er Shi (229 – 207 BC), given name Ying Huhai, was the second emperor of the Chinese Qin dynasty, reigning from 210 to 207 BC. The son of Qin Shi Huang, he was put on the throne by Li Si and Zhao Gao, circumventing his brother Fusu, who had been the designated heir. Upon Huhai's ascension, both Fusu and the popular general Meng Tian were killed on the orders of Li and Zhao, with Qin Er Shi's role in the assassinations remaining uncertain and controversial. A weak ruler, Qin Er Shi's reign was completely dominated by Zhao Gao, who eventually forced him to commit suicide. By the time of his death, the Qin Empire's power had lessened so much that his successor Ziying ruled as a king, not emperor.