Sun Chengzong (1563-1638), the name Zhisheng, the name Kaiyang, was a native of Gaoyang, Baoding (now Hebei). Outstanding patriotic general, national hero. From a young age, he had a strong interest in the military. When teaching at the border, "the cane and sword traveled under the plug, from the flying fox (Hebei Laiyuan North Flying Fox Pass) and the rejection of horses to Baideng (east of Datong, Shanxi)." And from the old road of Gangan (Datong, Shanxi), Qingbo (Qinghe, Hebei) to the south, to meet its heroes, and the generals and old soldiers, Zhou Xing border fortress, visit the key points, and untie the horse, wine and singing. It is used to inform the side of the matter" (1).

In the thirty-second year of Wanli (1604), Sun Chengzong was a jinshi and was awarded the Hanlin Academy for editing. In the first year of the Apocalypse (1621), he served as a Japanese official with Zuo Shuzi and entered the Shaozhan affair. At that time, Shenyang and Liaoyang fell one after another, and Sun Chengzong was appointed as a scholar of the military department and a scholar of Dongge University. After he took office, he complained about the shortcomings of the military system and operational command at that time, and sought reform, the main contents of which were: (1) "There are too many soldiers but no training, and too many salaries are not nuclear." This is to say that the army was poorly trained and the logistics supply was chaotic. (2) "Recruit and train with civilian officials by using generals, send civilian officials to command generals when they are in battle, and use military forces to advance borders, and increase civilian officials in the shogunate." He pointed out the mistakes of the command strategy of "using literature to contain force" at that time. (3) "Take the border to let the scriptures and care, and the day to ask the war to defend the court", pointing out the inappropriateness of "will be from the emperor". Therefore, he advocated "taking the power of the generals today." Choose one of the Shen Xiong who has the main strategy, and give it the thrift, which can be set up and biased below, so that the scribes do not use small views to touch the tomb." In addition, it was necessary to Fu Liaoxi, Liaomin, Jian Jingjun, etc., all of which were approved by Ming Xizong.

After Nurhachi captured Shenyang and Liaoyang, the Ming army was actually faced with the strategic choice of how to carry out military defense, that is, whether to defend the pass mainly and make an active defense, or whether to stick to the gate and make a passive defense. In this regard, the military generals of the Ming front had different opinions. The king of Liaoxi Jinglu advocated in Jin to "refuse slaves and take prisoners, block the pass and guard the pass".

The so-called "Fu Prisoner" means bribing Mongolia with money to deal with Houjin. The so-called "blocking pass" means building another gate outside the Shanhai Pass. Obviously, this is a policy of passive defense in disregard of the buffer zone of the Liaoning West Corridor. In the second year of the Apocalypse (1622), Wang Zaijin decided to build a city in Bali and reported it to the imperial court. This move was resolutely opposed by his subordinates Yuan Chonghuan, Sun Yuanhua and others. They thought that building the city was "not a strategy", and tried their best to dissuade it, and wrote a letter to Shoufu Ye Xianggao to complain about his intentions. Due to the unclear situation, it is difficult for Ye Xianggao to determine whether it is possible or not. Sun Chengzong then proposed to go to the field to investigate and make a decision again. After he arrived at Shanhaiguan, he immediately carefully inspected Shanhaiguan and the Balipu New Town advocated by Wang Zaijin, and then went to inspect the strategic terrain of Zhongqiansuo, Yibianshi and Loess Ridge. When inspecting Balipu New Town, Sun Chengzong had a fierce argument with Wang Zaijin:

"When the new city is completed, 40,000 people will be moved to the old city to defend it?" Sun Chengzong asked. Wang Zaijin replied: "No, we should set up more troops." Sun Chengzong asked again: "In this way, there will be 80,000 guards within eight miles." If it is not possible to defend it, then 40,000 new soldiers will defect to the old city, and the switch will be extended to the enemy, and the retreat will be closed to the enemy. Asked: "If this is the case, then the enemy will arrive and the soldiers will flee as before, and they will be used for heavy passes?" Answer: "Three villages will be built in the mountains to wait for the rout." Sun Chengzong asked: "If the soldiers are not defeated and build a fortress to wait for it, it is the defeat of the religion." And the rout can enter, and the enemy can also enter at the tail. Now we will not plan for restoration, draw a pass and defend it, and we will remove the fence completely. The day is noisy, there is Ning Yuhu in the east of Jidong?", severely criticized Wang's dangerous tendency to sit in prison and wait for death in the Jin Dynasty. "It's not difficult to be in Jin", but he is still stubborn.

In order to listen to the opinions of all sides, Sun Chengzong convened his generals to discuss how to defend. Yan Mingtai, the supervising army, mainly guarded Juehua Island (thirty miles east of Xingcheng, Liaoning, now known as Chrysanthemum Island), Yuan Chonghuan mainly guarded Ningyuanwei (now Xingcheng, Liaoning), and Wang Zaijin was mainly guarded by Zhongqiansu (now Suizhong County, Liaoning). Superintendents Xing Shenyan and Zhang Yingwu echoed Wang Zaijin's opinion. After comprehensively considering the opinions of all parties and weighing the pros and cons, Sun Chengzong expressed his support for Yuan Chonghuan's opinion of guarding Ningyuan.

Ningyuan, located in the middle of the Liaoning West Corridor, is "an inner arch rock pass, facing the sea in the south, between the surface and the inside, and is a winning shape" (1). Guarding Ningyuan is equivalent to choking the throat of this corridor, which can ensure the safety of Shanhaiguan, which is two hundred miles away. Therefore, Sun Chengzong's decision to defend Ningyuan was quite strategic.

When Sun Chengzong returned to Beijing, he clearly expounded to Xizong his strategic plan of holding Ningyuan and using the defenders of Juehua Island as horns and echoing each other, and formally put forward the strategic policy of "defending the Liao land with the Liao people and raising the Liao people with the Liao land", and suggested that Wang Zaijin be relieved of his post as the secretary of the military department and the economic strategy of Liaodong. Xizong accepted Sun Chengzong's advice and transferred Wang Zaijin to the post of secretary of the Nanjing Military Department. Since then, the discussion of building a city in Bali has come to an end.

After Wang Zaijin was transferred, the defense of Shanhaiguan adopted and implemented the strategy of Sun Chengzong and Yuan Chonghuan guarding the outside of the pass. After that, after several years of hard work, it was arranged into a solid Ning (Yuan) Jin (Zhou) defense line, which became an insurmountable obstacle for the Houjin cavalry. From Nurhachi to Huang Taiji, they have never been able to completely break this line of defense. After repeatedly hitting a wall, they were forced to look far away and be deterred. This line of defense not only ensured that Shanhaiguan was not attacked, but also basically stabilized the situation in the western Liaoning corridor for more than 20 years.

In August of the second year of the Apocalypse, Sun Chengzong was appointed as the governor of Liaodong. He immediately set about implementing his strategic plan of consolidating western Liaoning if he wanted to secure the closed gates, and if he wanted to restore eastern Liaodong, he must first consolidate western Liaoning, and actively deployed the Ningjin defensive line.

First of all, we have vigorously rectified the defense of closed doors. "At that time, the name of the soldiers was 70,000, and there was no discipline and a lot of money. Chengzong Dayue, hundreds of people escaped, and more than 10,000 soldiers were repatriated to Henan and Zhending. "It is a fixed military system, with barracks for five people, three thousand battalions, and fifteen battalions for three departments, and the general commander takes the battalion headquarters as the department. The soldiers will not leave the generals, they will not leave the commanders, and they will be easy to teach and audit. As a result of the rectification, the "soldiers and generals were cleared" and the combat effectiveness of the troops guarding the closed gate was enhanced.

In terms of the defense of the gate, "and the battle of the city, the construction of the city, the south of Haikou, the north of the corner of the mountain." The water is from the Wanghai platform out of Zhima Bay, surrounded by the sea on three sides, and the cannon is a horizontal attack. Lu Ze is the stone city of the three passes, and tens of thousands of people can be killed, and the door will be broken through at night. Outside the Beishui Pass, there is a mountain to build a trumpet platform 11, and a cannon is placed to prevent an external view." After five months of dismal operation, the situation of closing the door was stabilized, and the foundation was strengthened to restore the lost territory in western Liaoning.

At the same time, it is to build Ningyuan City. In September of the third year of the Apocalypse (1623), Sun Chengzong ordered his ancestor Dashou to repair Ningyuan, and ordered the garrison to restore the burned cities along the line from Shanhaiguan to Ningyuan as soon as possible. Summoning the Liao people back to their former homes, reclaiming barren fields, and rebuilding their homes. It also developed coal mining, salt boiling, and shipping to enrich the people's strength and ensure military needs. After the completion of Ningyuan City, Yuan Chonghuan was transferred to guard it. Sun Chengzong himself sat at the Shanhaiguan and prepared the front tun to act as his backing. Under the careful governance of Yuan Chonghuan, Ningyuan became an important military town that could be attacked and retreated.

With the consolidation of the city defense of Ningyuan, the Ming army's defense line continued to extend. In the summer of the fifth year of the Apocalypse (1625), Sun Chengzong sent the city of Jinzhou, Songshan, Xingshan, Shitun and Xiaolinghe. In this way, from Ningyuan to advance another two hundred miles, thus forming the Ningjin defense line with Ningyuan as the center.

In the past four years, Sun Chengzong has reused Yuan Chonghuan and a large number of loyal civil and military generals to prepare for border defense. "Since Chengzong went out of the town, closed the door and the police, China and North Korea feasted, and no longer worried about side affairs. "Not only has the original decline been reversed, but the whole situation is getting better and better. Just as he was determined to recover, he was hit by Wei Zhongxian.

Sun Chengzong's merits are high and powerful, and his reputation is full of government and opposition. Wei Zhongxian, in order to hold the court for a long time, wanted to pull Sun Chengzong to his side, so he tried many times, but was refused, so he held a grudge. In November of the fourth year of the Apocalypse (1624), Sun Chengzong toured west to Ji and Chang, and reported to enter the court on November 14 to celebrate the Wanshou Festival, and played the opportunity to meet the opportunity. Wei Zhongxian learned that he was afraid that he would support the army "Qingjun's side", and he was terrified, "crying around the royal bed, and he was also moved", so he immediately ordered the cabinet to draft a decree, and ordered him to return to the customs in the name of "leaving the land without a will, not the ancestral law". Sun Chengzong had no choice but to return. Afterwards, the eunuchs used this incident to attack Sun Chengzong for "supporting the army to Que, and the rebellion is obvious", but Xizong ignored it.

In August of the fifth year of the Apocalypse (1625), the defeat of Liuhe led to the resignation of Sun Chengzong. Ma Shilong, the chief soldier of Shanhaiguan, mistakenly believed the words of Liu Bo, a "prisoner" who had fled from Houjin, and sent troops to cross the Liuhe River and attack Yaozhou, but was defeated in the middle of the ambush. The eunuchs took the opportunity to make a big fuss, besieged Ma Shilong, and participated in the impeachment of Sun Chengzong. Sun Chengzong was extremely angry, and he asked for resignation. In September, he returned home.

After Sun Chengzong's resignation, Gao Di, the secretary of the Ministry of War, served as the Liaodong Economic Strategy. Gao Di was a man of letters, who did not understand military affairs and had never fought in war. As soon as he took office, he reversed Sun Chengzong's deployment and ordered the dismantling of the Ningjin defensive line. Except for Yuan Chonghuan, who was guarding Ningyuan, who refused to obey the order, all the other cities were evacuated. As a result, Sun Chengzong's hard work for several years was ruined, and the military situation of the Ming Dynasty in Shanhaiguan and outside the customs fell into a new crisis in an instant. It was only because of the bloody struggle of the vast number of soldiers headed by Yuan Chonghuan that the Ming army successively won the "Ningyuan Great Victory" and the "Ningjin Great Victory" in the first month of the sixth year of the Apocalypse and the fifth month of the seventh year of the Apocalypse, miraculously blocking the ferocious attack of the Later Jin, thus not only enabling the Ningjin defense line to withstand the test of war, but also enabling the Ming Dynasty to avoid a military rout caused by Gaodi's erroneous military decision.

In the second year of Chongzhen (1629), Huang Taiji led the army to avoid Ningjin, pretended to pass Inner Mongolia, broke into the Sei from the Xifeng Pass, and successively captured Zunhua, Yuan'an, Luanzhou, and Yongping, pointing directly to Beijing. and made a counter-plot, so that Emperor Chongzhen was imprisoned and finally killed Yuan Chonghuan. This matter is called "self-defeating". For a while, the Ming court was in chaos. And Yuan Chonghuan's imprisonment led to the discouragement of the army and the return of the soldiers. At this time of crisis, the Ming court once again used Sun Chengzong, "edict to guard Tongzhou with the former official and military department" to coordinate the overall situation. Sun Chengzong first knew the righteousness and calmed the morale of the army. After that, he coordinated the armies of all walks of life, acted jointly, and after several months of hard fighting, he achieved the "Zunyong Great Victory", and expelled the Houjin army from the pass in May of the third year of Chongzhen (1630).

After Sun Chengzong was reappointed as the commander of Liaodong, he still adhered to the principle of giving priority to active defense, continued to strengthen the Ningjin defense line, and was determined to rebuild the two cities of Daling River and Youtun, which were destroyed by Gaodi. In July of the fourth year of Chongzhen (1631), Ling Zu Dashou and others led 4,000 troops to guard the Daling River, and requisitioned 14,000 people to build the city. On August 6, only about 20 days after the start of construction, the city wall of the Daling River had just been repaired, and the pheasant moat was only half repaired, and the Houjin troops suddenly returned to the city, and began to besiege the city on the same day, and the Ming army hurriedly closed the door and refused to fight. "Cheng Zongwen, galloped to Jinzhou, and sent Wu Xiang and Zong Wei to rescue." However, Qiu Hejia, the governor of Ningyuan, "repeatedly changed his division, but Wei and Xiang were incompatible, so they were defeated in Changshan". By October, the Daling River had been besieged for three months, the defenders were exhausted of food, and Zu Dashou took a leave to return to Jinzhou, and "the city was destroyed". The loss of the Daling River caused a mutual conflict within the Ming court, "Yanchen pursued the blame for building the city, and the article discussed Hejia and Chengzong". Sun Chengzong even soothed the illness and asked for retreat. In order to calm the court discussion and allow him to return to his hometown, Sun Chengzong was excluded from power for the second time.

In the eleventh year of Chongzhen (1638), the Later Jin (Qing) soldiers went deep into the interior. On November 9, they besieged Goyang. Sun Chengzong, who was idle at home, led the whole city of soldiers and civilians to fight with him. Three days later, the city was broken, and Sun Chengzong was captured and strangled to death for refusing to surrender. After his death, he was called Wenzheng. (As Wen Zhong, see the biography of the Ming Dynasty) works include "Gaoyang Collection".

Sun Chengzong's military works include "Cheying Buckle Answer Co-editor". This is compiled from the records of his planning to counterattack Liaodong and discussing military issues with his subordinates when he was supervising Jiliao and running the defense of western Liaoning. The book consists of 108 questions and answers, consisting of four parts: "The General Explanation of the Che Battalion," "The 108 Deductions of the Che Battalion," "The 108 Answers of the Che Battalion," and "The 100 and 8 Sayings of the Che Battalion." Through questions, answers, explanations, diagrams, etc., the methods of organizing the car battalions, the arrangement of the battalion formations, the marching operations, and the logistical support are analyzed and explained in detail. In terms of operational guiding ideology, great importance has been attached to giving play to the role of firearms and the coordinated actions of various arms of the armed forces. For example, "using the car is using fire", "using fire is stacking array". The so-called "use of fire" means to carry forward firepower; the so-called stacking of formations means the overlapping arrangement of infantry, cavalry, and artillery, which are coordinated with each other and complement each other's strengths and weaknesses. Combat formations should also be adapted to local conditions, and various formations such as square, round, curved, straight, and sharp should be used flexibly and flexibly, thus showing people the era of the simultaneous use of firearms and cold weapons, and the rudiments of coordinated operations of infantry, cavalry, artillery, and other arms of the armed forces, which have important historical value in the history of the development of military thought.