2012-07-25 — As Chinese leaders were deciding to punish Vietnam, Vietnam overran Cambodia. Deng visited the US to complete diplomatic normalization between the two countries, and while there told President Carter that China would launch a limited attack on Vietnam (Carter 1982:206). Deng’s visit to the US drew criticism from Soviet Russia on 08 February, including a warning against “overstepping the forbidden line” in Vietnam (Hsu 1983: 825). The warning went unheeded as PLA tanks crossed the Vietnamese border on 17 February with the purposed of “teaching Vietnam a lesson.” Early Chinese attacks met weak resistance as Vietnamese border
troops were largely inexperienced, and as the PLA took the village of Lao Cai, 25km inside Vietnam, it became apparent that the Chinese objective was the capture of the larger village of Lang Son.
On February 21, the advance resumed against Cao Bang in the far north and against the all-important regional hub of Lang Son. Chinese troops entered Cao Bang on February 27, but the city was not secured completely until March 2. Lang Son fell two days later. On March 5, the Chinese, saying Vietnam had been sufficiently chastised, announced that the campaign was over. Beijing declared its “lesson” finished and the PLA withdrawal was completed on March 16.