Central Office for South Vietnam

Central Office for South Vietnam (abbreviated COSVN /ˈkɑːzvɪn/; Vietnamese: Văn phòng Trung ương Cục miền Nam), officially known as the Central Executive Committee of the People's Revolutionary Party from 1962 until its dissolution in 1976, was the American term for the North Vietnamese political and military headquarters inside South Vietnam during the Vietnam War. It was envisaged as being in overall command of the communist effort in the southern half of the Republic of Vietnam (South Vietnam), which included the efforts of both People's Army of Vietnam (PAVN), the Viet Cong, and the People's Revolutionary Party. Whether COSVN actually existed, and if so, where it was located at any one time, and how important it might have been, were contentious subjects, but in his memoirs the American commander in South Vietnam, General William Westmoreland, spoke of it as something whose existence and importance were not in doubt. Though the COSVN continued to exist in the later years of the war, it could not maintain Viet Cong activities, as the group was effectively destroyed in the aftermath of the 1968 Tet Offensive.

The headquarters was reportedly created in 1961 when the southern and central branches of the Lao Dong Party (the Vietnamese Communist Party) merged into the Central Directorate for the South. An advance element of the Party's Central Committee, the headquarters was chartered to direct VC guerrilla operations in South Vietnam. Major General Tran Luong came south in May 1961 to reorganize the structure of the Directorate and its subordinate regions, Military Regions 1, 2, 3, 4, 6 and 10, known collectively as the B-2 Front. In the process, he created COSVN.

In October 1963, COSVN organized the Military Affairs Party Committee (MAPC) and the Regional Military Headquarters. COSVN's first secretary, Nguyễn Văn Linh, served concurrently as the secretary of the MAPC, while General Trần Văn Trà became commander of the Regional Military Headquarters. Senior General Nguyễn Chí Thanh, a member of the northern politburo, arrived at COSVN in late 1963 or early 1964 to serve as southern regional political officer and became the dominant figure at the headquarters until his death during a visit to Hanoi in July 1967. This regional command structure reported through Thanh to the PAVN general staff in Hanoi. When Phạm Hùng replaced Thanh as the politburo's representative, he also became the first secretary of both COSVN and the MAPC.

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