First, the Maginot Line
The Maginot Line was a fortification constructed by France in its northeastern border area after World War I to defend against German invasion. The Maginot Line, which began construction in 1928 and was basically completed in 1940, cost 5 billion francs (1930s and 1940s currency), and its name comes from the then French Minister of War, A. -L． -R． Maginot's surname (1877–1932). The main body of the defensive line was hundreds of kilometers, the main part was in Thionville in eastern France.
The fortifications in the east of France before World War II were built of reinforced concrete and were very strong. Because of its high cost, it only defended the Franco-German border, while the Netherlands was backed by an Anglo-French coalition. Inside the defensive line there were all kinds of cannons, trenches, fortresses, kitchens, power stations, hospitals, factories, etc., and the passages were in all directions, and there were also tram passages in the larger fortifications.
Due to the rugged terrain of the Ardennes on the Franco-Belgian border, which is not easy to move, and the Belgian opposition to the construction of a defensive line on the Franco-Belgian border, the French army did not take much precautions, but never expected that the German army would break through. In May 1940, the Germans lured the Anglo-French forces to support the Netherlands, and then sneaked into the Ardennes Heights, and the Dutch Germans besieged the Allied forces in Dunkirk. The Maginot Line was rendered ineffective by the German attack on its back.
The Maginot Line consisted of the Metz Fortifications, the Saar Flooding Area, the Lauter Fortifications, the Lower Rhine Fortifications, and the Belfort Fortifications. The entire defensive line consists of a support zone (4 to 14 km deep) and a main defensive zone (6 to 8 km deep). The engineering structure is the strongest in the two fortification areas of Metz and Lauter.
The Saar flood zone was formed by natural river barriers and marshlands, and it was only after 1935 that fortifications began, with the weakest fortifications.
The Lower Rhine Fortifications were based on the Rhine, Rhône and Rhine Canals as a natural barrier, and only along the Rhine were supported by permanent firing fortifications.
In the most important areas of the metz and Lauter fortifications, a complex of ground and underground fortifications suitable for circular defense was constructed. The ground part is armored or reinforced concrete machine gun fortifications and artillery fortifications, and the underground part has several floors, including command posts, personnel lounges, food storage rooms, ammunition depots, ambulance stations, power stations, filter ventilation rooms, etc. There are passages between the fortifications, which are connected by electric vehicles. The weapons in the firing fortifications are specially designed and installed.
The entire defensive line built about 5,800 permanent fortifications for various purposes, with a density of 15 per kilometer of frontage. The top and walls of the strongest reinforced concrete fortifications were 3.5 meters thick, and the armor of the armored tower forts was 300 mm thick, both of which were able to withstand the direct hits of two 420 mm mortar shells.
The main anti-tank obstacles in the defensive line are anti-tank trenches, cliffs, cliffs and metal and concrete piles, and minefields are reinforced. Anti-infantry obstacles are generally metal piles or wooden pile barbed wire, and some areas are also equipped with electrified barbed wire.
2. The Suga Defense Line of the Maginot Line in the East
The defense fortifications were designed in 1933 by the City Sai Group of the General Staff Headquarters. Front-line positions and reserve positions are set up in the positions, and equipment such as shooting, observation, communication, transportation, camouflage, bunkers, and obstacles is set up, and light machine guns, heavy machine guns, and combat defense artillery fortifications are the main body to form a circular defense system. Building materials are mainly reinforced concrete, and natural obstacles are used as much as possible, supplemented by artificial obstacles to form permanent fortifications.
From 1934 to 1936, the Military Commission of the Nationalist Government mobilized several divisions to construct this national defense fortification. In 1937, after the outbreak of the Songhu war, the war could spread westward at any time. The Chinese military has tightened its grip on the reinforcement of permanent fortifications and the construction of field fortifications along the line.
The basic plan of the National Government in Nanjing is in Jiangsu, Zhejiang, and Shanghai, which is well known. In the 1932 128 Incident, the Japanese attack on Shanghai made the Nationalist government feel a great threat. After the end of the incident, because the Nationalist army in the Shanghai area had to be stationed in the regular army, only irregular troops such as the Shanghai Police Corps and the Shanghai Security Corps were maintained. In view of the threat of the Japanese army to the core area of the national government in the direction of Shanghai, the Nationalist government planned to build national defense fortifications in the Beijing-Shanghai-Hangzhou area in 1933 to meet the future attacks of the Japanese army.
From 1934 to 1936, the Nationalist army used four infantry divisions and a large number of engineer units to build a defense on the first line from Shanghai to Nanjing according to this plan. The plan divided the three defensive areas of Beijing-Shanghai, Shanghai-Hangzhou, and Nanjing, with Beijing-Shanghai as the defense focus, first building fortifications, and then allocating troops to defend. The Beijing-Shanghai area has three land and water routes of the Shanghai-Nanjing Railway, the Beijing-Shanghai Highway and the Yangtze River, and the Nationalist army expects this line to be the main route for the Japanese army to advance westward. In this direction, the north is the Yangtze River, the south side is the Taihu Lake, between the two lakes and swamps, the river network is longitudinal, if you can choose the point to build a defensive line, you can effectively resist or delay the Japanese attack.
Therefore, the Nationalist army finally chose the Suzhou to Fushan line to build the Wufu line position, and the Wuxi to Jiangyin line to build the Xicheng line position, and before and after these two national defense lines, there were forward positions and rear positions, and there were also warning positions.
In the Shanghai-Hangzhou Defensive Zone, it was a secondary defensive direction, but in order to connect with the Beijing-Shanghai Defensive Zone, two defensive positions were also constructed: the Zhajia Line (Zhapu to Suzhou via Jiashan) and the Haijia Line (Haiyan through Jiaxing to Wujiang).
In addition, in order to strengthen Nanjing's defenses, an arc position was formed on the line of Wulong Mountain, Qixia Mountain, Qinglong Mountain, Chunhua Town, Niushou Mountain, and Dashengguan, with the southeast as the main defensive direction; the Fukuo position took the Nanjing City Wall as the inner contour, and the Purple Mountain, Qilin Gate, Yuhuatai, Xiaguan, and Shogun Mountain Fortress Battery Lines were formed as outer contour positions, forming two lines of inner and outer cities and using each other; and building a bridgehead at Pukou on the north bank of the Yangtze River to block the ferry port.
Among the above-mentioned national defense fortifications, a relatively large number of permanent fortifications and some semi-permanent fortifications were constructed, focusing on the Wufu Line and the Xicheng Line, and using natural obstacles as much as possible to connect with the constructed fortifications. In the secondary direction, only few permanent fortifications were constructed. Before and after the start of the war, the garrison troops obtained the layout map of the national defense fortifications, and then supplemented them with field fortifications to open up the defense system.
In the case of the time, the positions constructed were centred on a number of infantry battalion positions, each consisting of three company positions and each company position consisting of three platoon positions. Each company and platoon position also has a first-line position and a reserve position, forming a deep echelon of subordinates. In addition to the infantry positions, the battalion positions also had various light and heavy machine guns, anti-aircraft guns, and mortar firing fortifications. The permanent fortifications were constructed of reinforced concrete, and the standard was to withstand 150 mm heavy artillery bombardment and 500 pound bombing. Among them, there are two kinds of heavy machine gun fortifications: orthographic and side firing; light machine gun fortifications have two kinds of single and multiple perforations; the anti-aircraft artillery fortifications have a combat room with a perforation of 70 degrees; observe all observation sides and two kinds of surrounding areas; the shelter can accommodate half a row of people to rest, and can also be used as a command.
In general, these fortifications should be all there, which were constructed by four infantry divisions of the Nationalist Army, including the 36th Division, the 57th Division, the 87th Division, and the 88th Division, as well as the 1st Independent Engineer Regiment, the Engineering School Practice Team, and the Gendarmerie Regiment.
The defensive fortifications built at that time could not be used immediately, but required the wartime garrison troops to be stationed in advance, find the position according to the national defense fortification garrison map, open up the permanent and semi-permanent fortifications with the excavated field fortifications, and then allocate the troops and combat materials, which can form an effective defense system.
At that time, after the construction of national defense fortifications was completed, the National Government was still relatively confident. In 1936, the Nationalist government divided the country into a number of national defense zones, with Zhang Zhizhong as the commander of the Beijing-Shanghai District, while Zhang Zhizhong worked in Suzhou under the name of the Camping Office of the Central Military Academy, and his subordinate units included 36th Division, 87th Division, 88th Division, 3 regular divisions, as well as the Shanghai Security Corps and the Jiangsu Security Regiment.
These troops were not only the builders of national defense fortifications, but also the permanent garrison of the State Government in the relevant areas, and at the same time the best equipped and trained troops of the National Army at that time. For example, the "German Mechanic Division" of the Nationalist Army, which is often said by the people, mainly refers to several units such as the 36th Division, the 87th Division, the 88th Division, and the Teaching Corps.
As a result, at the Battle of Songhu, the elite of the Nationalist army and the Japanese army lost a lot of money for several months and had to retreat strategically. However, in the process of retreat, the Nationalist government did not organize large-scale troops into the defensive line to rely on strong fortifications for defense, although it used a small number of troops to rely on the fortifications to resist the Japanese army for 5 days. But it is far from the original idea of spending a lot of money to build this defensive line.
Third, the underground Great Wall of the War to Resist US Aggression and Aid Korea
The officers and men of the Volunteer Army explored the use of tunnels in the lessons of the War to Resist US Aggression and Aid Korea, and as soon as the tunnel fortifications that had gradually developed from the anti-artillery holes and the hidden department appeared on the defensive positions of our army, they aroused the close attention and high praise of Commander Peng Dehuai.
In September 1951, the Volunteer Command issued instructions for the timely promotion of all participating units.
Since December, the volunteer army has built a large-scale solid fortification with tunnels as the backbone in the frontal positions, and by March 1952, the positions of the various divisions and regiments of the volunteer army have initially formed a relatively complete defense system that organically combines tunnels, communication ditches, trenches, etc., which has played an important role in the volunteer army's evasion of US air bombardment, reducing the enemy's ground shelling power, and preserving its own living forces.
At the end of August 1952, in addition to further building the tunnel fortifications of the units of the first echelon of the frontal front, the volunteer army also focused on the construction of tunnel fortifications on the east and west coasts, spanning the entire front of the Korean Peninsula for 250 kilometers, forming a position defense system with a depth of 20 to 30 kilometers, with the tunnel as the backbone and support points, creating a solid backing and obtaining reliable position support.
In March 1952, more than half a year before the start of the Battle of Shangganling, after receiving the task of defending the Wushengshan area, Cui Jiangong, commander of the 45th Division of the 15th Army, personally led people to survey the terrain and prepare for defensive operations. He was keenly aware of the importance of Shangganling to the defense of the entire Five Holy Mountains area, and figuratively compared Highland 597.9 to a right fist, believing that it was necessary to "take root" between Highland 597.9 and Highland 537.7 - field construction and digging tunnels.
In mid-April, the 15th Army held a special meeting on fortification, at which all the principal cadres at and above the company level attended the meeting, at which Commander Qin Jiwei made a special mobilization and demanded that all departments build an "underground Great Wall" that meets the requirements of the "seven defenses," that is, air defense, artillery defense, poison prevention, rain prevention, moisture prevention, fire prevention, and cold prevention, in accordance with the unified specifications of the volunteer army.
Since entering the position at the end of April, the entire 15th Army has conscientiously implemented the operational policy of "active defense, protracted combat, attrition and annihilation of the enemy, and preservation and improvement of itself" put forward by the military department.
The vast number of officers and men of the volunteer army shouted the slogan of "breaking through the belly of the mountain to build the Great Wall, hollowing out the ridge to secure my home."; they adapted themselves to local conditions and simplicity because of ugliness, made use of convenient equipment, relied on themselves, and tried every means to dig tunnels.
They collected enemy shrapnel and tank parts, set up their own blacksmith furnace to smelt iron, and the 45th Division alone made more than 1,000 hammers and more than 2,200 steel brazes. The fighters also risked their lives to collect unexploded ammunition and obtain 3700 kilograms of explosives, solving the urgent need for tunnel excavation.
The main support points of the basic positions of the Volunteer Army were constructed with 1 to 2 tunnels, and the squad positions had small tunnel shelters, and a considerable amount of ammunition supplies and other combat materials were stockpiled.
The tunnels provided an important barrier for the Volunteers to maximize the preservation of their living forces. In the face of the enemy's strong superiority in ground-to-air firepower, the tunnel, with its unique protective capabilities, provided a place for the officers and men of the volunteer army to avoid artillery fire, replenished ammunition supplies, and timely treated the wounded, creating favorable conditions.
From the repeated struggle between the enemy and us for control of the positions during the Battle of Shangganling, and in particular, the practice of our army in winning the war day and night, we can find that even if the enemy army occupies a superficial position, as long as the volunteer army firmly grasps the tunnel, the enemy army will not be able to consolidate the position, and once the time is ripe, the volunteer officers and men will recover their energy and find the fighter plane, and they will be able to annihilate the enemy army and seize the position again.
68 years have passed since the Battle of Shangganling, and looking back at those glorious years, the tunnels that have been baptized by the fire of war show the value of the mission and engrave the glorious achievements. As a basic protection unit, the tunnel has become a strong support for ensuring safety and stability and protecting important equipment and facilities in wartime.
Practice has proved that strong fortifications are only a means, "only by destroying the enemy in large quantities can we better preserve ourselves".
The British and French troops, who did not have a little initiative, passively hid in the strong fortifications, waiting for the enemy to come to the door, such as the Maginot Line, was not bypassed by the Germans? Spending that much money equals zero.
After building a solid public affair, but without making advance plans and making use of the solid fortifications, the Nationalist army that was defeated and retreated from the Battle of Songhu collapsed for thousands of miles, and when it reached the Sujia defense line, it could not even find the key and could not enter. Without initiative, without enthusiasm, without the belief that they dare to fight and win, the Beijing-Shanghai-Hangzhou defense line of the Nationalist army is equal to zero.
There was no national defense line in advance, and it was good at summing up the war in the war, first digging the cat's ear hole, then digging the anti-artillery hole, digging bigger and bigger, and finally discovering the magic weapon to save itself from destroying the enemy, turning the tunnel of passive defense into a passive defensive tunnel into a powerful weapon for taking the initiative to attack, destroy the enemy, fight night combat with the enemy, fight melee combat, fight encounter warfare, fight sneak attack warfare, fight annihilation warfare, and fight firepower warfare, and only Chairman Mao's people's army has done it.