Speaking of the Song Dynasty, people always think that the Song Dynasty was "poor and weak". The simplest evidence of "accumulation of weakness" is that the Great Song has never been able to recover yanyun sixteen states, which constitutes a heart disease of the great Song, for this land, several wars with the great Liao have failed; foreign expansion in other directions has never been successful, and finally because the north has no danger to defend and the country is destroyed. But if this "accumulation of weakness" seems to make sense, "accumulation of poverty" is not the case at all. Not only was it not poor, but the Great Song Dynasty reached the peak of the ancient Chinese dynasty in the economic, cultural, technological and other fields. Mr. Chen Yinke once praised: "The culture of the Chinese nation, which has evolved over thousands of years, was created in the world of Zhao and Song Dynasties. "The Great Song really deserves this kind of praise. Then why did such a peak Song people still have to fight back the Yanyun Sixteen Prefectures that Shi Jingyao had ceded? There's a reason for that.
Yanyun Sixteen States
The area circled by the red dotted line in the above figure is the sixteen states of Youyun and the sixteen cities:
Youzhou: present-day Beijing - Shunzhou: present-day Shunyi, Beijing
Ruzhou: present-day Yanqing, Beijing - Tanzhou: present-day Miyun, Beijing
Jizhou: Present-day Jizhou District of Jinzhou - Zhuozhou: Present-day Zhuozhou, Hebei
Yingzhou: present-day Hebei Hejian - Mozhou: present-day Renqiubei, Hebei
Xinzhou: present-day Zhuolu, Hebei - Yanzhou: present-day Huailai, Hebei
Wuzhou: present-day Xuanhua, Hebei - Weizhou: present-day Wei County, Hebei
Yingzhou: present-day Ying County, Shanxi - Huanzhou: present-day Eastern Shuozhou, Shanxi
Shuozhou: present-day Shuozhou, Shanxi - Yunzhou: present-day Datong, Shanxi
Then you look at this red line, which is the four-hundred-millimeter equal rainfall line, and its geographical distribution is roughly the Great Wall. In ancient times, if you lived north of the Great Wall, farming was not lively, so it had to be nomadic, otherwise it was a dead end. Therefore, the Liao State tried to seize the Sixteen Prefectures of Yanyun so that it could live a comfortable life. The location of the red circle in the picture above is roughly the position of Yanyun Sixteen Prefectures, don't look at him small, it is actually a knife against the neck of the Song Dynasty.
With it, the Song Dynasty can rely on natural dangers, with 10,000 elite soldiers can resist 100,000 iron horses, and if it is lost, the Liao State will have enough land to recuperate, according to records, although the land area of Youyun Sixteen Prefectures is only a small part of the territory of Daliao, its population accounts for more than 60% of the total population of Daliao, a plain with abundant water and soil, so that the strength of the Liao State has increased tremendously. Yanyun Sixteen Prefectures is actually a defensive line and granary, which can not only block the southern invasion of the nomadic peoples in the north, but also provide a large amount of grain and grass and war horses, and this is the reason why Zhu Di moved the capital to Beijing later.