The Central Office for South Vietnam (COSVN), loosely translated from the Vietnamese Văn phòng Trung ương Cục miền Nam ( literally meaning The Central Bureau of the South), was formed in May 1961 by Major General Trần Lương during the process of merging the southern and central branches of the Lao Động Party into the Central Directorate for the South. Officially known as the Central Executive Committee of the People’s Revolutionary Party, it was tasked with coordinating and directing all National Liberation Front (NLF), People’s Army of Vietnam (PAVN) and People’s Liberation Armed Forces (PLAF) military operations in Central and South Vietnam. It was a sought-after and obsessed-over prize for American and Army of the Republic of Vietnam (ARVN) forces.
Ultimately, however, COSVN remained elusive to capture. Far from the fortified compound Amerian intelligence assumed it to be in order to coordinate such a massive war effort, COSVN was spread over a vast area along Cambodia’s south-east border with Vietnam, relying on the same guerrilla tactics as the troops it oversaw: mobility and surprise.
During the early 1960s, COSVN was located in South Vietnam’s Tây Ninh Province, northwest of Saigon. During the period 1965–1970, the headquarters was based in and around the large Cambodian Mimot plantation, in what was called the “Fishhook” area on the Vietnamese/Cambodian border. During the Cambodian Campaign of 1970, COSVN moved further west into the interior of Cambodia, to the area around Kratié. Buildings were little more than bamboo huts and members of COSVN usually travelled between different office locations on foot or by bicycle. Bombing raids were ineffective against COSVN, and most special forces dispatched to the area on search and destroy missions wound up killed or returned with heavy casualties.