and auxiliaries, largely under a unity of command, active in South Vietnam. They were the subject of an ongoing debate within American intelligence, specifically, MACV and the civilian CIA sharply differed in their O/B appraisals of the VC. Composition of forces A complicating factor for an O/B was the composition of the VC and the PAVN. Regularly uniformed, 'conventional' soldiers were often called (in the parlance of the American military in Vietnam) 'main force' units. The majority of PAVN units were such, but only a disputed fraction of VC units were 'main force'. Troop designations used by the military might conform more to the geographic extent of their organization and command, e.g., provisional units (usually deemed soldiers) and local units (according to some: not so deemed, hence not to be counted). The vocabulary used to designate the different kinds of VC personnel was itself somewhat problematical. Not only are the terms taken from Vietnamese, French and English, but even in English, the terms used in a technical sense are often not consistent. A few different words may be used to describe the same kind of VC combatant, while a single word may designate different kinds. The terms may overlap in different ways, or be combined in different ways, apparently depending on the author, or the agency, or the locale, or the time period. The term 'combat guerrilla' may be understood as quite similar to conventional soldiers of a 'main force' unit. Yet 'guerrilla-militias' may signify part-time, ill-armed, poorly trained forces, which may even be deemed outside an O/B limited to combatants, and hence not counted. A recurrent issue was whether to count varieties of supporting forces. These could be differently equipped, or differently trained. They could be soldiers in training, or villagers who might fight or participate only part-time. Predominantly civilian VC were involved in combat support activity. Such positions included the political leaders, administrators, tax collectors, teachers, medical personnel, engineers, mechanics, etc. They were often designated as Viet Cong Infrastructure (VCI). Who should be counted in an O/B? "A characteristic of a guerrilla war is that the government side never knows how many of the enemy it faces." Or even who, as "every Vietnamese who passes in the street could be a guerrilla". ARVN & MACV: O/B to 1966 The Army of the Republic of Vietnam (ARVN) kept records of the opposing communist forces it faced within the borders