I don't know how many, but early years the N.Vietnam officers educated and trained by Chinese officers in many PLA Army Command Colleges is the TRUTH, to check their military records had proven. And our PLA soldiers worked and died in N.Vietnam also is the TRUTH.
And i remind u this guy, China PLA's senior general: 陈赓 大将(Cheng Gen) who ever was the senior staff officer in VPA, worked together with ur General Vo Nguyen Giap and ur countryfather Ho Chi Minh. This Chinese senior general Cheng Gen was a important guest for Ho Chi Minh in N.Vietnam.
When 1950 Ho Chi Minh and ur VPA kicked out from Hanoi city by French Army hiden in Northern jungle, China Mao sent this PLA's senior general and a team of China senior military officers came into N.Vietnam, worked together with ur Vientamese generals to re-make VPA's attack plans, This PLA's senior general Cheng Gen joint the Battle of Dien Bien Phu, he worked with Vietnamese general Vo Nguyen Giap.
And i tell u here, without China's help did u really think all weapons and food support from S.U can be safely shipped to N.Vietnam through the sea ? The whole Vietnamese Sea was blocked by U.S Navy 7th fleet ... all N.Vietnam's millitary supports from China and S.U by roads and railways, all from China's lands.
That's ALL 1950s~1960s Vietnam got helps and supports from Great China !!! Read more history.