从古到今,地理环境对国防建设、军事行动均有非常深刻的影响,尤其是在军事技术比较落后的古代,地理环境对战争的影响就更为显著。南宋北部国防的三大战区中,江淮战区主要防御长江下游地区,直接拱卫南宋首都临安和江浙重要经济区。南宋与金对于这一地区的控防是双方战争成败的关键之一,而控防的重点则在于对两淮地理环境的正确认识和合理利用,从某种意义上讲,南宋防守的成功是在结合传统的军事战略战术的基础上,在防守中合理利用锁钥地带与天险之优势,在百余年时间内保护了政权的安定。 Since ancient times, the geographical environment has a very profound impact on national defense construction and military operations. Especially in ancient times where military technology was relatively backward, the geographical environment had a more significant impact on the war. Among the three major national defense battles in the southern Song Dynasty, the Jianghuai Theater mainly defended the lower reaches of the Yangtze River and directly guarded the Linan and Jiangsu-Zhejiang important economic zones in the capital of Southern Song Dynasty. It is one of the keys to the success or failure of the war between the two sides that the Southern Song Dynasty and Kim defend and control the region. The key point of the prevention and control lies in the correct understanding and rational utilization of the geographical environment of the two Huaihe areas. In a certain sense, On the basis of combining the traditional tactics of military strategy and tactics, it is necessary to make rational use of the advantages of the key zone and the natural barrier in defense and safeguard the stability of the regime over a hundred years.