remained there until September and like its predecessor, conducted a demanding routine of internal security and cross-border patrols. Expansion of the regiment, 1960s The early 1960s were a period of strategic uncertainty and increasing commitments in South East Asia. Consequently, the Australian government re-introduced selective conscription in late-1964 and directed a significant increase in the strength of the Army. Yet unlike during the 1950s when National Servicemen bolstered the strength of CMF, under the new scheme they would serve for two years in the Regular Army instead. This substantial period of service for the regiment in Australia, Malaysia, and Vietnam saw the government direct the expansion of the regiment from four to nine battalions. By September 1965 the regiment consisted of seven battalions; by July 1966, eight; and by November 1967, nine. 4 RAR was formed in February 1964; 1 RAR abandoned the Pentropic Establishment (1,300 personnel) to revert to the Tropical Establishment (800 personnel), allowing 5 RAR to form in March 1965; 6 RAR was formed from a cadre drawn from 2 RAR in June 1965; 3 RAR assisted the formation of 7 RAR in September 1965; 8 RAR formed in August 1966; and 9 RAR was raised in November 1967. Vietnam War, 1962–1972 Although individual members of the regiment had served as advisors with the Australian Army Training Team Vietnam (AATTV) since 1962, it was not until April 1965 that the government announced that a battalion would be deployed to South Vietnam. Between June 1965 and March 1972 the units of the regiment would conduct sixteen rotations in South Vietnam, with the first seven battalions completing two 12-month tours, while 8 and 9 RAR would each serve one. Consequently, following a period of hurried training and administration 1 RAR joined the US 173rd Airborne Brigade at Bien Hoa Air Base northeast of Saigon in June 1965. After initially defending the airbase, 1 RAR steadily increased the scope of its patrols. For example, in January 1966, 1 RAR assaulted a large Vietcong (VC) headquarters complex in the Ho Bo Woods as a part of Operation Crimp; which the Americans hailed as the first strategic intelligence victory of the war. The battalion subsequently completed a 12-month-tour attached to US forces, during which it developed new tactics and techniques that later became standard for Australian battalions and supporting arms and services that would subsequently operate in Vietnam. In March 1966, Prime