I have read countless times that in 1979 the Chinese invaded Vietnam to “punish” the Vietnamese for having invaded Cambodia, a “client state” of the PRC.
I think that is common sense, however I have never read any detailed study about the day-to-day developments that led up to that war. Has anyone produced such a study? I would think that it would be difficult as I suspect that the relevant documents in both Vietnam and China are probably still classified.
Nonetheless, I got a sense of some of the things that were probably happening then by looking at some of the issues of the newspaper Hà Nội mới that the National Library of Vietnam has digitized.
The Chinese invasion of Vietnam began on 17 February 1979. On that very day, the front page of Hà Nội mới featured an article about a visit by a delegation of Vietnamese government officials, led by Prime Minister Phạm Văn Đồng, to Phnom Penh to meet with members of the post-invasion government there.
On the 18th, the front page of Hà Nội mới is divided between articles on the meetings taking place in Phnom Penh and the Chinese invasion.
We see the same “divided news” on the 19th,
As well as on the 20th when the Vietnamese government delegation returned to Hanoi.
Then starting from the 21st the coverage is 100% about the Chinese invasion.
It seems obvious to me that these two events – the visit to Phnom Penh and the invasion of Vietnam – must be related. So I looked around to see what people have written about this.
I found an article in Asian Survey from 1980 by Les Buszynski (a graduate student at the London School of Economics and Political Science) called “Vietnam Confronts China” in which he noted that “On February 18, 1979, the day after the Chinese invasion of Vietnam, Le Duan and Pham Van Dong signed a 25-year Treaty of Friendship and Cooperation between the two countries under which both parties were ‘duty bound to help each other whole-heartedly.’ The treaty gave the Vietnamese a facade of legality for now they could admit that their forces were operating in Cambodia at the request of the new regime to clear the country of bandits.”
It can’t be a coincidence that the Chinese invaded on the day that Vietnamese government officials were meeting with their counterparts in Cambodia. My guess would be that, like Buszynski said, the Vietnamese were trying to establish some form of legal legitimacy in Cambodia. What I wonder is if it was precisely this move that led the Chinese to start the invasion.
That said, there must have been communications between Beijing and Hanoi before this. It would be fascinating to know what was communicated at that time.