context: A few days before the war, Chinese President Deng Xiaoping made his famous statement that "China is going to teach a lesson to Vietnam." In the early morning of February 17, 1979, after artillery preparation, the People's Liberation Army of China (PLA) launched an invasion of the northern provinces of Vietnam. They immediately met fierce resistance from border guards and militias. The invasion took place in several directions. The main ones were: Laokai, Kaoban (from the Detian waterfall) and Langshon. In general, the fighting went almost along the entire line of the Vietnamese-Chinese border. During the first three days of the war, the Chinese managed to capture the provincial center of Laokai and advance in some places 15 km into the territory of Vietnam [1]. However, after this, the pace of advance sharply decreased. After the introduction of reinforcements and at the cost of heavy losses, the PLA seized another provincial center by the end of February - Kaobang. The culmination of the invasion came on March 4, when after fierce battles Langshon was captured, from where the Chinese troops opened the road to Hanoi. The extent to which the Vietnamese are concerned about the fall of Langshon is evidenced by the fact that a general mobilization was announced on 5 March in Vietnam. But on the same day, China officially announced the cessation of the offensive and the beginning of the withdrawal of troops. Despite this, the fighting continued until the completion of the withdrawal of Chinese troops from Vietnam, which occurred, according to Chinese data, on March 16.
question: When did the Sino-Vietnam War begin?
answers.text: February 17, 1979