At the time of the outbreak of the Korean War, Chen Geng was serving as a military adviser in Vietnam, and the most important thing was that Chen Geng would go to Vietnam, mainly at the invitation of Ho Chi Minh, who personally told Chairman Mao that he only needed Chen Geng to go to Vietnam to help. In this way, Chen Geng led the Chinese military delegation to Vietnam, and with the help of Chen Geng's military experience, the military situation in Vietnam was gradually reversed, which shows how outstanding Chen Geng's military ability is. As the situation in Vietnam got better and better, Chen Geng did not need to continue to stay in Vietnam for a long time, and then he bid farewell to Vietnam and seamlessly entered the Korean battlefield.
The reason why Chairman Mao sent Chen Geng to the Korean battlefield so urgently was because the situation on the peninsula had become extremely complicated at that time. After all, the superiority of the US army's weapons and equipment has indeed caused a lot of losses to the volunteers, and Mr. Peng has put great pressure on the front-line commanders because of this, which is not conducive to the development of the war situation in the future.
Therefore, at this time, Chairman Mao believed that Chen Geng, who was known as a pistachio, would be able to effectively change the situation if he could go to the Korean battlefield, and in this way Chen Geng entered North Korea. After Chen Geng arrived in North Korea, he used his humorous personality to quickly mingle with many people, and in casual conversations, he grasped first-hand information about the Korean battlefield. It's just that he didn't expect the situation in Vietnam to change again at this time, and Chen Geng had to return to Vietnam because of this. The situation in North Korea is not optimistic, and the continuous flow of reinforcements from the United Nations forces has increased the pressure on the volunteers.
The shortcomings of the volunteer army were also exposed at this time, the lack of material supplies, which greatly limited the operation of the volunteers, and Mr. Peng personally returned to the north for this reason, just to get more supplies, Chen Geng was also ordered to enter the DPRK, but due to his physical reasons, he could not go with Mr. Peng, and then he went to the front line in North Korea alone. At this time, it was the end of the Fifth Campaign, and the losses of the Volunteer Army were enormous. When Mr. Peng's anger was in full swing, it was Chen Geng who adjusted it, and Chen Geng found that trench tactics and cat's ear hole tactics may be able to change the current situation and reduce the losses of the volunteers themselves.
Chen Geng led the volunteers to build more than 200 kilometers of tunnels, so that they could use these tunnels to transport a large amount of materials to the front line, even if the US military dispatched air power, it would not be possible to discover the existence of these tunnels. At this time, Chen Geng was needed to return to deal with the lock-up matter, and Chen Geng left North Korea again, but what he didn't expect was that he entered North Korea for the third time soon after. At the operational meeting, he proposed that tunnel operations should be combined with traditional combat methods.
In this way, the tunnel can not only transport materials, but also prevent fire, poison and water, and most importantly, there is also a living area, so that the volunteers can both attack and defend. In this way, after Chen Geng entered the DPRK three times, the volunteers built a replica version of the Great Wall on the Korean Peninsula to effectively block the offensive of the US army. I believe that the U.S. military did not expect that Chen Geng would complete this construction work after entering the DPRK three times and solve the problem of the shortcomings of the volunteers.
It can also be seen from this incident that Chen Geng is indeed a very capable person in terms of operations, although he did not stay in North Korea for a long time, but he quickly discovered the problem and proposed effective solutions.