北宋东京外城上的瓮城及其形制考略

An Analysis of Dong Jing City's Barbicans and Their Layouts in the Northern Song Dynasty

东京(今河南开封)外城始建于后周,北宋神宗时期,为进一步增强其军事防御功能,又在城门和水门之外加筑了瓮城。金元之后的多次黄河水患,把外城及瓮城深深地淤埋在了地下。近年来,开封市文物工作者相继探明了外城部分城门的瓮城,基本搞清了其位置、结构和布局等,同时还对外城西墙新郑门瓮城遗址进行了考古发掘。根据考古结果并结合文献记载可知,外城上的瓮城种类丰富、形式多样,总体可分为城门和水门两类。城门又分正门和偏门两种,瓮城形制或方或圆,有直门两重和屈曲二门、屈曲三门之分。水门瓮城形制有"拐子城"和双曲尺形,因位置不同又有水门洞两侧并列两个陆行门和仅在水门洞一侧设一个陆行门的区分。北宋东京外城上瓮城的普遍使用,标志着我国古代瓮城筑造技术的成熟,不仅首开了在中原腹地尤其在都城上大量使用瓮城的先河,而且因为东京城的特殊地位,还使瓮城在以后都城甚至地方城池建设中普遍使用,至明清之际,瓮城遂成为全国各地各级城池修建城门时的定制。

The outer city of Dong Jing（today Kaifeng,Henan Province）was built during the Later Zhou Dynasty.During the reign of Shen Zong Emperor of Northern Song Dynasty,barbicans were added outside of the city gates and water gates to further enhance the citys defense capabilities.Multiple floods after the Jin and Yuan Dynasty buried the outer city and the barbicans deeply beneath the ground.In recent years,Kaifengs Archeology and Artifact Team has detected part of the barbicans of the outer city,basically ascertained its location,structure,and layout,and has started the excavation of the Xin Zheng Gate relic.According to archeological evidence and archives,there are a variety of barbicans in the outer city which could mostly be categorized into city gates and water gates.There are two kinds of city gates：front ones and side ones.The barbicans are either round or square,and can have two gates facing each other or two to three gates not facing each other.The water barbican layouts are eitherGuaizi（twisted）City＂or resemble the form of two trisquares,and because of their different locations they had either two land gates on the sides of the water gate or just one land gate by the water gate.The common appearance of barbicans on the Northern Song Dong Jings outer city signals the maturity of the barbican construction technology in ancient China.It not only foreshadows the wide application of barbicans in Central Plain cities and the capital,but is also introduced to capitals and even townships after the Northern Song Dynasty due to the importance of the Dong Jing City.During the Ming and Qing Dynasty,barbicans have become a required component of all levels of cities.