In early 1956 the French built Commando School at Nha Trang was re-established with US military assistance to provide physical training and ranger instruction for up to 100 students. Early the following year President Ngo Dinh Diem ordered the creation of a special unit to conduct clandestine external operations. Initial parachute and communication training for 70 officers and sergeants was conducted at Vung Tau; 58 of these later underwent a four month commando course at Nha Trang under the auspices of a US Army Special Forces Mobile Training Team. Upon completion, they formed the Lien Doi Quang Sat so 1 (First Observation Unit) on November 1957 at Nha Trang. The unit was put under the Presidential Liaison Office, a special intelligence bureau controlled by President Diem and outside the normal ARVN command structure. The commander was Lt. Col. Le Quang Tung, an ARVN airborne officer and Diem loyalist. Many of the Unit's members came originally from northern Vietnam, reflecting its external operations orientation.

In 1958 the Unit was renamed the Lien Doan Quang Sat so 1, or First Observation Group, reflecting its increase to nearly 400 men in December. By that time the Group was seen as an anti Communist stay behind force in the event of a North Vietnamese conventional invasion; however, because of its privileged position the Group stayed close to Diem and rarely ventured into the field.

By 1960 it was apparent that the main threat to South Vietnam was growing Viet Cong insurgency; the Group abandoned its stay behind role and was assigned missions in VC infested areas. Operations were briefly launched against VC in the Mekong Delta, and later along the Lao border.

In mid 1961 the Group had 340 men in 20 teams of 15, with plan for expansion to 805 men. In October the Group began operations into Laos to reconnoiter North Vietnamese Army logistical corridors into South Vietnam. In November the Group was renamed Lien Doan 77,or 77 Group, in honor of its USSF counterparts. Over the next two years members were regularly inserted into Laos and North Vietnam on harassment and psychological warfare operations. Longer duration agent missions, involving civilians dropped into North Vietnam, also came under the Group's auspices.

The Group's sister unit, 31 Group, began forming in February 1963. Following criticism of 77 Group's perceived role as Diem's 'palace guard', both groups were incorporated into a new command,, the Luc Luong Dac Biet (LLDB) or Special Forces, on 15 March 1963.
The LLDB after President Ngo Dinh Diem

In the wake of the coup the Presidential Liaison Office was dissolved and its function assumed by the ARVN. The LLDB was put under the control of the Joint General Staff and given the mission of raising paramilitary border and village defense forces with the USSF. External operations were given to the newly formed Liaison Service, also under the JGS. The Liaison Service, commanded by a Colonel, was headquartered in Saigon adjacent to the JGS. It was divided into Task Force 1, 2 and 3, each initially composed of only a small cadre of commandos. In 1964 the JGS also formed the Technical Service (So Ky Thuat), a covert unit tasked with longer duration agent operations into North Vietnam. Commanded by a Lieutenant Colonel, the Technical Service comprised Group 11 (Doan 11), oriented toward agent operations in Laos and eastern North Vietnam; Group 68 (Doan 68 Thang Long), another infiltration unit; and the Coastal Security Service, a maritime commando group at Da Nang attached to the Technical service with its own contingent of PT boats for seaborne infiltration.

The post Diem LLDB was restructured for its proper role as a source of counter insurgency instructors for paramilitary forces. By February 1964, 31 Group had finished training and was posted to Camp Lam Son south of Nha Trang. In May the Group became responsible for all LLDB detachments in I and II Corps. A second reorganization occurred in September when 31 Group was renamed III Group and given responsibility for the Special Operations Training Center at Camp Lam Son. Now 77 Group, headquartered at Camp Hung Vuong in Saigon, became 301 Group. In addition, 91 Airborne Ranger Battalion, a three company fast reaction para unit, was raised under LLDB auspices in November. Total LLDB force strength stood at 333 officers, 1270 non commissioned officers and 1270 men. The LLDB command at Nha Trang was assumed by Brig. Gen. Doan Van Quang in August 1965.

By 1965 the LLDB had become almost a mirror image of the USSF. LLDB Headquarters at Nha Trang ran the nearby Special Forces Training Center at Camp Dong Ba Thin. LLDB 'C' Teams, designated A through D Company, were posted to each of South Vietnam's four Military Regions; each 'C' Team had three 'B' Teams, which controlled operational detachments at the sub regional level; 'B' Teams ran 10 to 11 'A' Teams. 'A' Teams were co-located with USSF 'A' Teams at camps concentrated along the South Vietnamese border, where they focused on training Civilian Irregular Defense Force (CIDG) personnel.

In addition, the LLDB Command directly controlled the Delta Operations Center with its Delta teams and the four company 91 Airborne Ranger Battalion, both were used by Project Delta, a special reconnaissance unit of the US Military Assistance Vietnam Studies and Observation Group (MACV-SOG), which operated deep in VC/NVA sanctuaries.

On 30 January 1968 the Communists launched their TET general offensive across South Vietnam. Caught celebrating the lunar New Year, the Saigon government was initially ill prepared to counter the VC/NVA attacks. When Nha Trang was hit on the first day the LLDB Headquarters was protected by 91 Airborne Ranger Battalion, recently returned from one of its Project Delta assignments. At only 60 percent strength the Airborne Rangers turned in an excellent performance, pushing the major Communist elements out of Nha Trang in less than a day. The battle, however, cost the life of the battalion commander and wounded the four company commanders.

After a four month retraining in Nha Trang three companies from 91 Airborne Ranger Battalion were brought together with six Delta teams and renamed 81 Airborne Ranger Battalion. In early June the new battalion prepared for urban operations in Saigon after a second surge of Communist attacks pushed government forces out of the capital's northern suburbs.

On 7 June the Airborne Rangers were shuttled into Saigon and began advancing toward VC held sectors around the Duc Tin Military School. After a week of bloody street fighting, much of it at night, the Airborne Rangers pushed the enemy out of the city.

Following the Tet Offensive 81 Airborne Ranger Battalion was increased to six companies, and continued to be used as the main reaction force for Project Delta; four companies were normally assigned Delta missions while two remained in reserve at LLDB Headquarters.

From the book: SPIES AND COMMANDOS, How America Lost the Secret War in North Vietnam, (Modern War Studies) by Kenneth J. Comboy and Dale Andrade.

81st Ranger Group and Vietnamese Special Forces Association Website