fanzhen

thumb|400px|The 48 fanzhen (Military Districts under Buffer Towns) of late Tang dynasty, as of the 15th year of Emperor Xianzong's reign (820 CE).

Fanzhen (), also called fangzhen (), was a system of decentralized governance in Medieval China that involved strategic military districts and commanderies along the empire's borderland areas administered through highly autonomous regional governors known as jiedushi during the Tang dynasty (618–907 CE). Primarily designed to be buffer regions shielding the politically and economically vital heartlands, these districts came under the control of increasingly influential provincial military commissioners, who became ambitious warlords, rebels and even usurpers during the late Tang period. The phenomenon of fanzhen domination has been termed fanzhen geju (; lit. "secessionist occupation of barrier towns") by historians.