Shang Yang (c. 390-338 BC), a Legalist philosopher and statesman of the state of 秦国 qín​guó whose reforms paved the way for the unification of China by the 秦朝 qín​cháo; also known as 卫鞅 wèi​yāng or Gongsun Yang.

major political or legal reform; historically refers to top-down institutional changes such as those led by 商鞅 shāng​yāng or the 戊戌变法 wù​xū​biàn​fǎ in 1898