On this day in 1979, the Chinese People's Liberation Army (PLA) launched an attack on Vietnam, marking the PLA's first major combat operation since the Korean War.
The PLA mobilized around 200,000 troops and 200 tanks for the invasion.
The invasion was carried out in two eastern and western directions, commanded by Yang Dezhi and Xu Shiyou.
Although Vietnam quickly mobilized its forces, the PLA advanced 15-20 kilometers into Vietnam, with mainly fighting occurring in the provinces of Cao Bằng, Lào Cai, and Lạng Sơn.
The PLA employed a strategic ploy in which it captured the heights above Lạng Sơn, surrounded the city, and paused, hoping to lure the Vietnamese into reinforcing it with units from Cambodia.
After three days of intense fighting, the PLA captured Lạng Sơn and occupied Sa Pa.
During the withdrawal, the PLA used a scorched-earth policy, destroying local infrastructure, looting useful equipment and resources, and severely weakening the economy of Vietnam's northernmost provinces.
The PLA crossed back into China on March 16, and both sides declared victory, with China claiming to have crushed the Vietnamese resistance and Vietnam claiming to have repelled the invasion using mostly border militias.
Although Vietnam outperformed the PLA on the battlefield, the PLA's seizure of Lạng Sơn allowed the Chinese to move into the Red River Delta and thence into Hanoi. However, had the PLA decided to attack Hanoi, the PLA would have suffered huge losses.
The Soviet Union, although it did not take direct military action, provided intelligence and equipment support to Vietnam.
During the Sino-Vietnamese War, the Soviet Union deployed troops at the Sino-Soviet and Mongolian-Chinese border to show support for Vietnam and tie up Chinese troops.
The Soviet Pacific Fleet also deployed 15 ships to the Vietnamese coast to relay Chinese battlefield communications to Vietnamese forces.
Although the Soviet Union supplied material to Vietnam, they believed that there was no way they could directly support Vietnam against China due to the distances involved. Any reinforcements would have to cross territory controlled by China or US allies.
Vietnam was crucial to Soviet policy but not enough for the Soviets to take direct action to defend their ally.
#ThisDayInHistory
February 17, 1979
I had never known this before, thanks!
I will enjoy looking deeper.
I was waiting to hear the blaming of the USA for the incident.