Construction of the Song Huai River Defense Line (1137)

Timeline

1. 1137Lin'an · ZhejiangAfter Wanyan Zongbi's southern campaign was repulsed, Emperor Gaozong and the grand councilors formally adopted the strategy of using the Huai River as the north-south boundary and holding Huainan, ordering generals to take charge of defense construction and military farming by sector.
2. 1137Fortresses along both banks of the Huai River · Huai River basinSong forces built fortresses, ramparts, and arrow towers at Huai River crossings and strategic points, setting up beacon towers and patrol systems. Han Shizhong, Yue Fei, and other commanders each held a section, forming a defense network in depth.
3. 1137Huainan military farming districts · HuainanThe Song army implemented military farming in Huainan, reclaiming wasteland to supply its own grain and easing the burden of rear-area transport, allowing garrison troops to hold the line long-term—a key measure for the sustainable operation of Southern Song frontier defense.