護國北門：南宋時代鎮江地位的躍昇

The Northern Gate of State Defense: The Growing Importance of Zhenjiang in Southern Song China

鎮江是長江下游的轉輸城市。宋室南遷後，由於立國環境和江南運河二個因素的結合，讓鎮江頓時成為聯絡四方的轉輸樞紐。又因便於聯結淮邊與都城及據江扼敵的地理優勢，自紹興十一年（1141）起不僅是宋金使路及南北貿易必經要道，宋廷更基於戰略部署，在此駐守重兵，設置都統制司及總領所，遂使鎮江由區域性城市，躍昇為護國北門，在經濟、政治、軍事等方面均具全國性的影響力。到蒙元滅宋統一中國後，由於政經型態的轉變，江南運河淤塞嚴重，難以發揮南宋黃金水道的運輸功能，鎮江的戰略地位與轉輸優勢遂告消退。本文從轉輸功能、戰略部署、政務架構及漕運與民生四個面相，探討鎮江在南宋崛起的要素兼對地方社會的影響。

In the Southern Song dynasty, Zhenjiang, located at the meeting point of the Jiangnan Canal and the Yangtze River, became the transportation center of the lower Yangtze region, thereby serving as the nexus that connected the capital Lin'an and the frontiers in the Huai River region. From 1141 onwards, ambassadors of the Southern Song and Jin dynasties as well as merchants traveling around or through the region usually passed through Zhenjiang. Due to this strategic importance, the Song court stationed a significant number of soldiers along with installing a commander-general and commissariat in the city. Zhenjiang thus transformed into a city with economic, political, military, and other functions and was crucial to the state by being its ''northern gate.'' However, after the establishment of the Yuan dynasty following the defeat of the Song in 1279, the importance of Zhenjiang quickly diminished as the Jiangnan Canal silted up, dismantling Zhenjiang's status as a transportation center. This article analyzes the history of Zhenjiang from four perspectives: river transportation, military deployments, administrative structures, and the impact of canals on the livelihood of the people. In this way, shifts and influences in Zhenjiang society during its growth and later decline from the 11th to 13th century are explored.