If referring to the Vietnam War then the answer is September 26th 1959. That is the start date of the war anyway. There had been unrest and civil wars since far earlier however with the background leading to the Vietnam war begining in the 1940s.
Anti Communist Forces:
South Korea
USA
Australia
Philippines
Thailand
Republic of China
Khmer Republic
Kingdom of Laos
Communist Forces
North Vietnam
Viet Cong
Khmer Rouge
Pathet Lao
People's Republic of China
North Korea
Most historians generally accept the starting date for the war as 1961.
NVA and VC.
Vietnam and Cambodia
Basically, the Vietnamese sides, north and south, each had allies and supporters. These allies joined with the troops in Vietnam. The US was on the side of the south. They lost.
It was fighting for democracy and against communism.
In Vietnam, with action extended into Laos and Cambodia. It was know as the Vietnam War. But it turns out that this military activity was designated as "a police action" and the U.S. was not at war with any of the countries where America was fighting.
North Vietnam/VC vs allies
Vietnam was fighting in the war with Russia, and Russia was battling the British men.
The anti-communist countries fighting the communists in the war, were: The US, Australia, New Zealand, Philippines, Thailand, South Korea, and South Vietnam.
Air war North Vietnam. Ground war South Vietnam.
Part of the cold war.
We were fighting for our freedom but America was the biggest threat to the communist countries
people
No.
NVA and VC.
After the war, there was a reunification of Vietnam. So the answer is "One country".
Vietnam and Cambodia
It was a civil war of sorts, with North Vietnam fighting to unify the country with the help of allies China and the Soviet Union - and South Vietnam, defended by western and Asian allies in the South East Asia Treaty Organization. (SEATO)