《读书》第三期刊朱新华先生《南宋的北界》一文,指出以长江为南宋国境的北界之误,完全正确。实际上,存在这样的误解的前贤和学者还不止夏承焘、刘永济二先生,也不止对南宋一朝。人们往往以为历史上的“南北朝”(泛指一切南北对峙的政权)都是以长江为界的,其实恰恰相反,大多数朝代或时间内南北的界线并不是长江。 The third issue of “Reading”, Mr. Zhu Xinhua, entitled “The Northern Song of the Southern Song Dynasty,” pointed out that it is absolutely correct to regard the mistake of the Yangtze River as the boundary of the northern boundary of the Southern Song Dynasty. In fact, there are more than those who have such misunderstanding, such as Xia Chengtao and Liu Yongji, and not only to the Southern Song Dynasty. People often think that the history of the “North and South Dynasties” (referring to all the regimes that are confronted by the South and the North) is based on the Yangtze River. In fact, on the contrary, the boundary between North and South in most dynasties or time is not the Yangtze River.