Speaking of national defense fortifications, we cannot fail to mention the 128th Shanghai Anti-Japanese War in the 21st year of the Republic of China (1932).

Although the 19th Route Army fought bravely, because the Central Army was at an absolute disadvantage in all aspects in terms of army, navy, and air force compared with the Japanese, the 19th Route Army still suffered defeat after the Japanese army increased its troops three times and changed commanders four times, and Zhang Zhizhong led the "Imperial Forest Army" Fifth Army to join, but it failed to reverse the decline, and Chairman Chiang was even ready to move the capital to Luoyang.

However, in the end, the United States, Britain, France, Germany and other Western powers were unwilling to monopolize the rich middle and lower reaches of the Yangtze River in the Central People's Republic of China, so they joined forces to put pressure on the Japanese government.

The 128 Incident finally ended in armistice talks, but Chairman Chiang was still frightened into a cold sweat, and the elder Chiang deeply felt that there was a huge gap between China and Japan in terms of national strength and military strength, and if it had not been for the intervention of the Western powers at that time, Xiao Ri would have rushed to Luoyang, so Chairman Chiang made up his mind to change this unfavorable situation.

It was also a coincidence that at that time, Zhang Shaoshuai was quite loyal to Chairman Chiang, Feng Yuxiang, Yan Xishan, Li Zongren and other local warlords were quite honest, and the domestic politics were still relatively calm, so Chairman Chiang began to make every effort to reorganize the army, and with the help of the German advisory group, he made a five-year reorganization of the army, and decided to reorganize 60 German armament divisions within five years!

On paper, the German armament division has more than 17,000 soldiers, six infantry regiments, and one battalion of artillery, engineers, communications, spies, baggage, and cavalry.

In addition to reorganizing the army, Chairman Chiang also decided to build national defense fortifications in the Beijing-Shanghai-Hangzhou area, because Chairman Chiang knew very well that there was a huge gap between China and Japan in terms of national strength, and even if he had formed 60 German armament divisions as he wished, in the future Sino-Japanese war, China would definitely be on the defensive side, so it was also necessary to use strong fortifications to have a lasting attrition of the enemy.

To preside over the construction of such a huge defense fortification, it is necessary to have a military strategist with outstanding reputation and ability.

At that time, there were only three and a half people who were recognized as military strategists or qualified to serve as chief of general staff in the military circles of the Central People's Republic of China, among which Jiang Baili was the most prestigious, but unfortunately he had the experience of overthrowing Chiang, Chairman Jiang did not trust him, Liu Bocheng was the most capable, but unfortunately he had defected to the Communist Party, Bai Chongxi's prestige and ability were slightly worse, and he was also the second leader of the Gui family, Chairman Jiang still did not trust, except for these three people, there was only Zuihou half of the military strategist, he was Yang Jie.

However, Yang Jie was in a mood because of the loss of competition with He Yingqin at that time, and he didn't even do the least on-site investigation, so he spent two and a half days drawing a few lines on the drawings and making a "Beijing-Shanghai-Hangzhou fortification plan." In other words, he was ready to build Nanjing into a super fortress, but he was criticized by his sworn enemy He Yingqin, saying that he was not outdated in form and rigid in thinking.

Chairman Chiang also felt that Yang Jie was passive and did not give him Jiang a certain face, so he drove him to Europe to "investigate", and then Chairman Chiang began to ask the German advisory group, the Germans were much more rigorous, they spent several months on the spot, Zuihou put forward an extremely rigorous defense plan, according to this defense plan, with the military strength and firepower level of the Japanese army at that time, there was no hope of breaking through the defense line to Nanjing, but this plan also had a fatal shortcoming, that is, the cost was too high. The government had to go without food or drink for years to save money for building defense fortifications.

After a large number of on-the-spot investigations, they put forward a plan that reasonably expounded and distinguished the possible offensive direction of the Japanese army and the focus of the entire defense plan.

The plan believed that the Japanese army was most likely to attack Nanjing from Shanghai along the Yangtze River and the Beijing-Shanghai Railway, so it advocated the construction of national defense fortifications in Fushan, Changshu to Wuxian, and Jiangyin to Wuxi, and to set up offensive positions and rear assembly positions in the front and rear, forming two national defense lines with battalion and regiment-level fortification groups as the main body, which were the Wufu Line and the Xicheng Line.

The plan also did not ignore the possibility of the Japanese army landing from Hangzhou Bay, and advocated the construction of coastal fortresses in Zhapu, Pengpu, Tuolin and other places, and the construction of national defense fortifications in Zhapu, Jiashan to Suzhou, Haiyan through Jiaxing to Wujiang, and the construction of offensive positions and assembly positions in front and rear, which is the Jiazha Line and the Haijia Line.

In addition to these four defense lines, in Nanjing, it is necessary to build a compound position and a peripheral defense line, the complex position is based on the city wall, and the outer defense line starts from the Great Shengguan Pass, through Niushou Mountain, Fangshan, Chunhua Town, Tangshan Town to Qixia Mountain to form an arc-shaped fortification group, relying on the Yangtze River moat, forming a complete defense circle.

Chairman Chiang adopted the plan, and began construction in the 23rd year of the Republic of China, and was basically completed in the 25th year of the Republic of China.

The four defense lines are mainly composed of battalion-level fortification groups, and a small number of important areas are strengthened into regiment-level fortification groups, and all heavy machine gun nests, artillery positions, observation posts, shelters, and ammunition depots are all made of reinforced concrete to form permanent fortifications.

The hòu degree of the roof of all permanent fortifications is more than one meter, which is enough to resist the bombardment of 150mm caliber heavy artillery and 500 pounds of aerial bombs, and the top hòu of the underground shelter is more than two meters, which is enough to withstand the bombardment of 1000 pounds of aerial bombs

If 10 to 20 divisions could have relied on the defense line to fortify the defense, it would have been difficult for the Japanese army to quickly cross the defense line, but due to the serious strategic mistake of Commissar Chiang, these four defense lines have hardly played a role.

It was no accident that the 19th Brigade encountered it at Xujiabin, as the 51st Division, which was fortified near Suzhou, and the troops near Changshu, all encountered a similar situation.

Because they did not know the specific location of the fortifications, the officers and men of the national army could only dig up and seal the soil bags everywhere, and as a result, many graves were dug up, and even if they dug up the fortifications, there was no key, and they still could not enter the fortifications

A large number of permanent fortifications built along the Wufu line, only a very small number of them can be used in the end, and the very few permanent fortifications that have been enabled have basically not played their due role, because no matter how strong the fortifications are, they must be guarded, and these national troops defeated from the Songhu battlefield have long since lost their fighting spirit.

Speaking of which, the fortifications on the Wufu line have more or less always played a little role, and the most regrettable thing is that the two defense lines of Jiacha and Haijia, because the landing of the Japanese army in Jinshanwei was too sudden, and the main forces of the national army had all been transferred to Huxi at that time, so the Japanese army crossed these two defense lines almost bloodlessly.

When the Japanese army on the southern front marched around the south bank of Taihu Lake and captured Yixing, the Xicheng line, which was also the strongest defense line in Zuihou, could not continue to hold on, the only thing to be thankful for was that the Sichuan army blocked the Japanese army on the southern front in Guangde and Si'an, and the Jiangyin fortress also firmly locked the Yangtze River, which won time for the retreat of the main force of the national army.

By the end of November, the main forces of the Nationalist army that had withdrawn from the Songhu battlefield had basically retreated to Ji'an and Chuzhou.

At this time, Chairman Chiang had already made up his mind to defend Nanjing after holding three staff meetings, and the Nanjing Garrison Command, with Tang Shengzhi as the commander-in-chief, was also officially inaugurated, but the troops subordinate to the garrison headquarters at that time were only the 71st Army, the 72nd Army, and the 78th Army, in addition to the military police headquarters.

Although the 71st Army, the 72nd Army and the 78th Army are all military-level formations, each army actually only has one division, namely the 87th Division, the 88th Division and the 36th Division.

Of course, such a small number of troops could not hold Nanjing, so Chairman Jiang asked Tang Shengzhi, which army do you want?

Tang Shengzhi has been fighting with Chairman Jiang for decades to be the boss, and he can be described as an old traitor, and he knows Chairman Jiang's character well, so he asked Chairman Jiang rhetorically: Will you take the teaching corps of the Central Military Academy with you?

Chairman Jiang trembled in his heart, gritted his teeth and said, Here you go!

Tang Shengzhi asked again, do you still take Yu Jishi's 74th Army with you?

Chairman Jiang gritted his teeth and stomped his feet, saying, the 74th Army will also leave you behind! In this way, Chairman Chiang's most closely related troops were left in Nanjing, and he thought to himself, he couldn't let these troops fight out, and he had to leave them cannon fodder troops, so the 66th Army, the 83rd Army of the Guangdong Army, and Xu Yuanquan's 2nd Army were also assigned to Tang Shengzhi

For such a result, Tang Shengzhi had already had Yujian, holding the most elite and capable of fighting more than a dozen divisions at that time, Tang Shengzhi still had great confidence in holding Nanjing for a few months, in his opinion, the Japanese army should almost be tired of the division's veterans, and the national army could almost organize a counteroffensive.

If he can complete the Jedi counterattack in Nanjing, then he Tang Shengzhi will be enough to go down in history!

So at the press conference held on March 27, Tang Shengzhi said in a righteous and awe-inspiring manner that he may not be able to guarantee anything else in Nanjing, but there are two things he will definitely be able to do: first, he will not be chaotic in the face of danger and difficulties; Second, there will be no retreat without the commander's order, and he will swear to live and die with Nanjing!