Chinese debacle?
There were many reasons why it could be argued that the war was a disaster for the Chinese armed forces. First, the Chinese military was using equipment and tactics from the era of the Long March, World War II and the Korean war, which meant for example, that only Chinese officers carried assault rifles, while the Vietnamese had more modern Soviet (and U.S.) equipment, combined with assault rifles for every soldier. Second, under Deng's order, China did not use their naval power and air force to suppress enemy fire, neutralize strong points, and support their ground forces. Therefore, the Chinese ground forces were forced into absorbing the full impact of the Vietnamese forces' firepower. Third, the PLA lacked adequate communications, transport, and logistics. Further, they were burdened with an elaborate and archaic command structure which proved inefficient in the FEBA (Forward Edge of Battle Area). Their maps were 75 years old. Runners were employed to relay orders because there were few radios—those that they did have were not secure. Fourth, China was one of the only two countries in the world at the time that lacked the military rank system (the other being Albania), and thus commands were not effective. Fifth, the Cultural Revolution had significantly weakened Chinese industry, and military hardware produced suffered from poor quality, and thus did not perform well. Finally, the Chinese struck back at an enemy that was highly trained, experienced, and confident due to successive victories in wars with France, the U.S., and Cambodia.