[4-A] The three-way division was the most commonly used method of categorizing the Communist forces. (See U.S. Army, _The Viet Cong_, p. I:52.) A USMAAG document published during this period, however, divided the Viet Cong into two somewhat broader categories--main forces and guerrillas. Both local force units and village activists were classified as guerrillas under this system. (USMAAG, Vietnam, _Tactics and Techniques of Counterinsurgent Operations_, p. II-5.) Other sources tended to make more elaborate divisions. (See Pike, _Viet Cong_.) After early 1962 the activities of these Viet Cong military and paramilitary forces were carefully coordinated with Communist political activities on the national level by a Central Office for South Vietnam (COSVN).[4-B] From its headquarters, believed to have been located northeast of Saigon in Binh Duong Province, COSVN exercised direct control over six military regions (MRs). Designated MR-5 through MR-9 (arranged in a north to south pattern) with an additional Saigon-Gia Dinh Special Zone, the Communist military regions served essentially the same purpose as the government’s corps tactical zones. Within these six regions COSVN utilized a province and district structure only slightly different from that of the Diem government to exercise administrative and military control. At each level within this organization a small, disciplined Communist political committee orchestrated the activities of its subordinate military units with the actions of its political apparatus. [4-B] COSVN apparently was established in March. Prior to this the NLF had functioned through two separate geographic headquarters--Interzone V, responsible for roughly the northern three-quarters of South Vietnam, and the NAMBO Interzone, responsible for the area roughly described by the forested hills and Mekong Delta physiographic regions.