After 1949 the PRC was the channel to supply the Viet Minh and later the PAVN (NVA). Much of what they funneled was Soviet made along with stuff from other East Bloc countries. As I recall, the PRC did man some NVA air defense sites near the China VN border. But it is well to remember that the Vietnamese never liked the Chinese and fairly soon after the war ended fought a war with them. They also backed competing factions in Cambodia. From what I have read, the PRC did not design the campaign or advise Giap on Dien Bien Phu.

Le Duan was the Viet Minh leader among the stay behinds in the South after the Geneva accords. By the late 50s the Diem regime was crushing the Viet Minh and all Le Duan's pleading from the South to Ho and Giap had no effect. As a result Le Duan went to hanoi and personally convinced the Politburo to support a real effort in the South. So Le Duan and Giap were not always on the same side in the internal politics of the DRVN and the Party. In fact, I recall recently reading that Le Duan saved Giap from being cashiered for cause putting Giap both in his debt and in fear of Le Duan. In any case, Giap was both commander of the NVA and Defense Minister in 1972 which made him the responsible officer for the Easter offensive.

As to Giap as a strategist: I like Ralph Peters' comment put in the words of Meade in Hell or Richmond that Grant did not know how to win battles but he did know how to win the war. I think that applies to Giap overall (although he did know how to win the battle of Dien Bien Phu). The way I understand Giap as a strategist is as a national strategist, not simply or even primarily as a military strategist. Whether he had read CvC or not, he was a Clausewitzian.

Cheers

JohnT