Jin Dynasty Fortress System

Timeline

1. 1181–1183Jin Zhongdu (present-day Beijing) · North ChinaDuring Emperor Shizong's Dading era (records of frontier ditch construction around 1181), the Jin dynasty built forts and garrisoned troops along the northern border and maintained the frontier ditch line, guarding against southern incursions by northern nomadic tribes, laying the groundwork for the later main frontier ditch works.
2. 1194–1198Jin northeastern circuit frontier ditch line · NortheastEmperor Zhangzong launched large-scale construction of the Jin frontier ditch (Jin Great Wall): in Mingchang 5 (1194) an edict convened officials to deliberate, from Cheng'an 1 (1196) Wanyan Xiang oversaw construction along the entire line, and it took shape around Cheng'an 3 (1198). The northeastern section ran from present-day eastern Inner Mongolia to western Jilin, adding walls, ditches, and garrison forts on the basis of Dading-era frontier forts.
3. 1189–1211Jin northern frontier · Northern FrontierAfter accession, Emperor Zhangzong continued northern defense policies; in Cheng'an 5 (1200) he built the Wushabao Great Wall (a second defense line) on the basis of the existing frontier ditch on the northwestern route; but after Genghis Khan unified the Mongol tribes in 1206 and launched a major southern campaign, the Jin army suffered a disastrous defeat at the Battle of Yehuling in Da'an 3 (1211), and the frontier ditch line failed to effectively stop the Mongol cavalry, with the Mongol-Jin war fully erupting from then on.