Chen Geng, deputy commander of the Chinese People's Volunteers, was Mr. Peng's right-hand man, and although he did not personally participate in the Korean War, his actions had a profound impact. When Mr. Peng led the Chinese volunteers to Korea, Chen Geng was in Vietnam to assist in the fight against France, and did not return to Beijing until the end of November 1950. Subsequently, he was sent to the Korean front, but he was concerned about the war in Vietnam and returned to Vietnam again in January 1951. Although he did not stay in Korea for a long time, was not directly involved in commanding battles, and only made one expedition to the Korean battlefield, his departure coincided with the outbreak of the fourth battle in the Korean theater.
In the initial stage, the Chinese volunteers annihilated more than 20,000 enemies, but the U.S. military quickly launched a counterattack with its superiority, which brought great trouble to the Chinese volunteers. Chen Geng was unable to personally lead the team to support due to a leg injury, so he had to let Deputy Commander Wang Jinshan lead the Third Corps into the court. Until August 1951, Chen Geng's leg injury gradually recovered, and he went to North Korea for the second time to meet with Peng Lao. At that time, the Korean War had entered a stalemate stage, and the Chinese volunteers were not good at positional warfare. Chen Geng had been exposed to tunnel tactics during the Huaihai Campaign, and thought that he might be able to deal with the current situation.
And Mr. Peng was worried for a long time, and Chen Geng thought of this tactic that might solve the war. Chen Geng personally went to the front line to inspect and accidentally discovered the soldiers' improved "cat's ear hole", which can meet the functions of concealment and storage ammunition at the same time, and the passage connecting the two cat's ear holes forms a simple fortification. Inspired by this, Chen Geng conceived the prototype of tunnel tactics and personally presided over the construction of more than 200 kilometers of tunnels to solve the problems of defense and supply for the soldiers. Although this project was only a small test, Chen Geng wanted to expand the scale, but was transferred back to China due to other things.
Until April 1952, Mr. Peng returned to China to recuperate due to enteritis, and Chen Geng re-entered the DPRK and took over Mr. Peng's work. After arriving at the Korean front, Chen Geng quickly convened a commander-level conference to comprehensively promote tunnel tactics. Under the guidance of Chen Geng, the scale of construction far exceeds the past, and the new tunnel is more perfect, integrating solid, waterproof, anti-virus, restaurant, warehouse, toilet and other functions, which can be described as solid. The U.S. and South Korean armies realized the seriousness of the problem, and no matter how many shells they poured, the positions of the Chinese volunteers did not seem to be affected.
Especially in the Battle of Shangganling, the firepower of the US army exceeded the highest level of World War II, flattening the hill by nearly two meters, but it still could not make the Chinese volunteers lose their combat effectiveness, relying on a strong tunnel like a fortress. Before the tunnel was promoted, the U.S. military could kill a soldier of our army with about 40 to 60 shells, and after the tunnel was formed, the U.S. military needed to shoot 660 shells to kill a volunteer soldier. It can be said that the "tunnel" is the lifeline of the Chinese volunteer soldiers.
According to statistics after the end of the Korean War, the Chinese volunteers built 1,290 kilometers of tunnels during the war, plus trenches and communication trenches, the total length exceeded 6,000 kilometers, comparable to the Great Wall. [Reference: "The Biography of Chen Geng", "General Chen Geng", "Korean War"].