Fajia (Chinese: 法家; pinyin: fǎjiā), or the School of fa (incl. law, method), often translated Legalism, was a bibliographic school of primarily Warring States period classical Chinese philosophy, including more administrative works traditionally said to be rooted in Huang-Lao Daoism. Addressing practical governance challenges of the unstable feudal system, their ideas 'contributed greatly to the formation of the Chinese empire' and bureaucracy, advocating concepts including rule by law, sophisticated administrative technique, and ideas of state and sovereign power. They are often interpreted along realist lines. Though persisting, the Qin to Tang were more characterized by the 'centralizing tendencies' of their traditions.
The school incorporates the more legalistic ideas of Li Kui and Shang Yang, and more administrative Shen Buhai and Shen Dao, with Shen Buhai, Shen Dao, and Han Fei traditionally said by Sima Qian to be rooted in Huang-Lao (Daoism). Shen Dao may have been a significant early influence for Daoism and administration. These earlier currents were synthesized in the Han Feizi, including some of the earliest commentaries on the Daoist text Daodejing. The later Han dynasty considered Guan Zhong to be a forefather of the school, with the Guanzi added later. Later dynasties regarded Xun Kuang as a teacher of Han Fei and Qin Chancellor Li Si, as attested by Sima Qian, approvingly included during the 1970s along with figures like Zhang Binglin.