In response to the Vietnamese invasion of Cambodia, China launches an invasion of Vietnam.
Tensions between Vietnam and China increased dramatically after the end of theVietnam War in 1975. Attempting to expand its influence, Vietnam established a military presence in Laos; strengthened its ties with China's rival, the Soviet Union; and toppled the Cambodian regime of Pol Pot in 1979. Just over a month later, Chinese forces invaded, but were repulsed in nine days of bloody and bitter fighting. Tensions between China and Vietnam remained high throughout the next decade, and much of Vietnam's scarce resources were allocated to protecting its border with China and its interests in Cambodia.
Tensions between Vietnam and China increased dramatically after the end of theVietnam War in 1975. Attempting to expand its influence, Vietnam established a military presence in Laos; strengthened its ties with China's rival, the Soviet Union; and toppled the Cambodian regime of Pol Pot in 1979. Just over a month later, Chinese forces invaded, but were repulsed in nine days of bloody and bitter fighting. Tensions between China and Vietnam remained high throughout the next decade, and much of Vietnam's scarce resources were allocated to protecting its border with China and its interests in Cambodia.
From Wikipedia:
The Sino–Vietnamese War, also referred to as the Third Indochina War, was a brief but bloody border war fought between the People's Republic of China and the Socialist Republic of Vietnam, from February 17, 1979, to March 16, 1979. The Chinese launched the offensive in response to Vietnam's 1978 invasion and occupation of Cambodia, which ended the reign of the PRC-backed Khmer Rouge.The Chinese invaded northern Vietnam and captured some of the northernmost cities in Vietnam. On March 6th, China declared that the gate to Hanoi was open and that their punitive mission had been achieved and retreated back into China. Both China and Vietnam claimed victory in the last of the Indochina Wars of the 20th century