Fifty years ago on Tuesday, the arrival of an unusual Australian soldier in Saigon had heralded the start of Australia's most controversial military deployment.
For the following three years, Colonel Ted Serong, a counter-insurgency expert and true Cold War warrior, was to command the Australian Army Training Team Vietnam (AATTV), whose 30 members arrived three days later.
Serong, who died in 2002, remains an enigmatic figure.
After leaving the Australian Army in 1968, he went on to consult on counter-insurgency for the US military and South Vietnamese government, departing Saigon by helicopter on April 29, 1975, the day before the city fell to North Vietnamese forces.
In his later years, he advocated assorted anti-communist and right-wing causes, serving as patron of a pro-gun citizens' militia group.
The AATTV, commonly referred to as ''The Team'', was to become Australia's most decorated unit of the Vietnam War. Four members won the Victoria Cross - the only VCs awarded in Vietnam.
So how did the Vietnam engagement come about?
The Melbourne historian Bruce Davies, a team member in 1967-70, said the then US secretary of state, Dean Rusk, visited Canberra in May 1962, pointedly asking what Australia, an alliance partner, might do to help in the struggle against the communist threat in Laos, Cambodia and Vietnam.
The answer initially appeared to be some aid but not much more. Australia offered a few military advisers but eventually settled on a team of 30.
The contribution was actually accepted against the wishes of the US military.
''The American commander up there at the time said he didn't want third-country nationals coming in and polluting the atmosphere with their way of doing things,'' Davies said.
The US Department of State eventually swayed the argument with its call for additional nations to be seen to be helping.
There were further arguments about where the Australian team would be located - all over the place, as it turned out - and whether it would teach the South Vietnamese according to US doctrine.
The team had said it would, but supplemented that with Australian techniques.
Concerned about casualties, Canberra initially barred team members from accompanying Vietnamese forces in field operations.
That ban was lifted in 1964, although Serong tacitly approved involvement from mid-1963. By then, after Sergeant Bill Hacking was shot dead on June 1, 1963, Australia had experienced the first of more than 500 casualties of the Vietnam War.
Hacking's death remains controversial. The official verdict was an accident but Davies has no doubt that he was an unhappy soldier traumatised by his service in Korea and took his own life.
Australia's first combat casualty was Warrant Officer Kevin Conway, killed on July 6, 1964, in a Viet Cong attack on a remote US special forces base at Nam Dong near the Laotian border. The action forms the basis of the key battle scene in the much-criticised John Wayne movie The Green Berets.
Davies, author of a new history, Vietnam: The Complete Story of the Australian War, attributes the outstanding record of the team to a number of factors.
The unit, which started at 30, peaked at 200 but averaged around 100, was in Vietnam for a decade.
Some of its members were deployed for up to 18 months.
Three served for nearly five years total and five served for more than three years in total.
All were older, experienced soldiers with an average age of 33 against 22 for members of the taskforce.
Further, team members operated throughout South Vietnam, many in areas where the action occurred on a daily basis.
''On one day, you could have had people from the training team in five different battles. They were experiencing a far wider range of warfare,'' Davies said.
He might be speaking heresy, but Phuoc Tuy province, where the Australian taskforce operated, was a backwater of the war, compared with some areas where team members served, particularly in the central highlands and along the demilitarised zone and Laotian border.
The last team members departed Vietnam on December 18, 1972, following the decision of the new Whitlam Labor government to withdraw remaining combat forces.
Throughout that period 996 Australians and 11 New Zealanders served in the team.
Unlike taskforce soldiers, whose dealings with the local people were limited, team members became very close to those they were training and this peremptory withdrawal still rankles.
At that time, the team was training Cambodian forces and one member was out on patrol with a local unit.
''A Land Rover turned up and they said, 'Get in - we're going home.' We left the Vietnamese and everyone else like a bunch of bloody rats, just bailed out,'' Davies said.
Captain Ian Gollings, 26, was a member of the initial deployment. He had served in Malaya, with experience of tactics used to defeat the communist insurgency.
Gollings subsequently spent six months at the US Army Infantry School learning how the US conducted counter-insurgency.
He was then posted to the Special Air Service Regiment.
Team members flew from Australia to Singapore, then travelled aboard a Pan Am civilian flight into Saigon.
''That was quite amusing,'' Gollings recalled.
''The Australian government had not yet announced we were going to Vietnam. We boarded this flight going to Saigon in civilian clothes and during the flight we changed into our uniforms. That created some consternation among the other passengers, these 30-odd young men disappearing into the toilets and coming out in uniform.''
In Saigon, team members spent a few days being briefed and issued equipment before being posted to their various locations.
Gollings, now living in Canberra, ended up near the northern border, training Vietnamese regional force soldiers in infantry tactics. He spent 16 months in Vietnam, subsequently serving with the Special Air Service in secret operations in Borneo.
Team members believed Australia faced a grave threat from international communism sweeping down through Asia.
''We all went to Vietnam in the belief that we were doing our bit for Australia,'' Gollings said.
''We were convinced there was a serious threat. It was called the domino theory in those days. With hindsight, a lot of us would say perhaps it wasn't exactly like that.''
Vietnam - The Complete Story of the Australian War, by Bruce Davies with Gary McKay, 704 pages, Allen and Unwin, RRP $49.99