The Sino-Vietnamese War, also known as the Third Indochina War, was a brief border war fought between the People’s Republic of China and the Socialist Republic of Vietnam in early 1979. China launched the offensive in response to Vietnam’s invasion and subsequent occupation of Cambodia in 1978. Chinese Vice-premier Deng Xiaoping saw this as a Soviet attempt “to extend its evil tentacles to Southeast Asia and…carry out expansion there,” which reflected the long-standing Sino-Soviet divide.
In response to China’s attack, the Soviet Union sent several naval vessels, but felt that there was no way that they could directly support Vietnam against China, as the distances were too great to be an effective ally, and any kind of reinforcements would have to cross territory controlled by China or U.S. allies. The only realistic option would be to indirectly restart the simmering border war with China in the north.
On February 17, a Chinese force of about 200,000 supported by 200 Type 59, Type 62, and Type 63 tanks from the Chinese People’s Liberation Army (PLA) entered northern Vietnam. China lost 6,954 men in the war while Vietnam saw 42,000 military deaths and 10,000 civilian deaths. The war ended with victory for both sides as the Chinese withdrew from Vietnam and Vietnam continued to occupy Cambodia, with very little territorial changes for both.
In China, the war is referred to as the Defensive Counterattack against Vietnam.