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.
These buffer zones were designed to safeguard the economically and politically crucial central regions, which eventually fell under the control of rising influential provincial military commanders who became ambitious warlords, rebels, and even usurpers during the late Tang period.