What advice does Yu Qian have for border defense?

After the Ming Dynasty overthrew the rule of the Yuan Dynasty in the Central Plains, the remnants of the Yuan Dynasty retreated northward to the Mongolian Plateau, which was called "Northern Yuan" in history. Later, the "Northern Yuan Dynasty" was divided into two parts: Tatar and Vara. By the middle of15th century, Walla gradually became powerful and became a great enemy in the north of Ming Dynasty.

At the beginning of the Ming Dynasty, the northern border defense line was within the jurisdiction of Datong Town, with Longmen, Wanquan and Fu Xuan (now Zhangjiakou and Longguan in Hebei Province) as the farthest in the northeast and Dongsheng and Yun Chuan (now Liangcheng and Helinger in Inner Mongolia) as the farthest in the northwest. However, after Yongle, under the pressure of the north, the defense line gradually moved inward, and Datong and Fu Xuan, which were originally in the second line of defense, became the first line. When Yu Qian was governor of Shanxi and Henan, he noticed the importance of Datong in border defense. However, due to too many things under his jurisdiction, it is difficult to concentrate on strengthening Datong's border defense affairs. He suggested to the court that full-time governors of Fu Xuan and Datong should be set up to comprehensively plan the local border defense. After his suggestion was adopted, he supported Luo Hengxin, the newly appointed governor of Xuanda University, to restore officers and men to settle fields, enrich their salaries, and strengthen the construction of border defense castles in order to fight against the intrusion of Walla.

Yu Qian has great ambition to serve the country since he was a child. When he was young, he admired Wen Tianxiang's patriotic spirit of sacrificing his life for his country. In the 19th year of Yongle (142 1), Yu Qian was a scholar at the age of 24, and was appointed as the imperial adviser of Shanxi Road. Later, he was ordered to patrol Shaanxi and wrote to the court to impeach the government troops in the border towns of Shanxi and Shaanxi, disturbing the people at will and undermining the stability of the border areas. The emperor sent people to investigate and arrested some illegal officials. Because of Yu Qian's frankness and attention to state affairs everywhere, he offended a group of powerful people, especially eunuchs, who hated money even more. In the eleventh year of orthodoxy (1446), Yu Qian went to Beijing as the governor of Shanxi and Henan, and recommended Wang Lai and Sun as temporary representatives. Wang Zhen took the opportunity to instruct General Political Officer Li Xi to falsely accuse him, because "he has not been promoted for a long time, so he arbitrarily elected others to vent his dissatisfaction." Yu Qian spent three months in prison for this. Later, people and officials in Shanxi and Henan signed bail petitions. Wang Zhen was forced to release Yu Qian and demote him to Shao Qing of Dali Temple. Later, at the request of Shanxi and Henan officials and people, he was restored to his post. In the 13th year of orthodoxy (1448), due to Vara's continuous invasion to the south, the court ordered Yu Qian to enter Beijing and appointed him as the left assistant minister of the Ministry of War to directly participate in planning border affairs.