Question: what was the difference between the viet cong and the north vietnamese?
Answer: As explained in the responses here, the North Vietnamese (NVA or PAVN) were the formal army of North Vietnam while the Viet Cong (short for Vietnamese Communist) was the guerrilla Army of South Vietnam. Actually, the Viet Cong was formed from the remnants of the Viet Minh who had successful fought the French.