Central Office for South Vietnam

The Central Office for South Vietnam (COSVN) was, according to Gen. Tran Van Tra of the People's Army of Viet Nam (PAVN), the southern branch of the Vietnam Workers' Party Central committee, which represented the Party and conducted all military and political activities in South Vietnam. This was a semimobile field headquarters, not, as some U.S. missions to destroy it seemed to suggest, a smaller version of the Pentagon Building.

Originally, the National Front for the Liberation of Vietnam was a broad-front organization, and, prior to the rise of militant Vietnamese Buddhism, the main organized opposition to the Republic of Vietnam government. Until January 1962, its Communist component was the "southern branch of the Vietnam Workers' Party", but the Southern party then split off into the Peoples' Revolutionary Party of South Vietnam. Nevertheless, it was increasingly clear, that the North Vietnamese Politburo had overall control of dau trinh theory as well as the operational headquarters. The PAVN clearly controlled logistics on the Ho Chi Minh trail, the planning of which began in May 1959.