September 2, 1945 - Japanese sign the surrender agreement in Tokyo Bay formally ending World War II in the Pacific. On this same day, Ho Chi Minh proclaims the independence of Vietnam by quoting from the text of the American Declaration of Independence which had been supplied to him by the OSS -- "We hold the truth that all men are created equal, that they are endowed by their Creator with certain unalienable rights, among them life, liberty and the pursuit of happiness. This immortal statement is extracted from the Declaration of Independence of the United States of America in 1776. These are undeniable truths."
Ho declares himself president of the Democratic Republic of Vietnam and pursues American recognition but is repeatedly ignored by President Harry Truman.
September 13, 1945 - British forces arrive in Saigon, South Vietnam.
In North Vietnam, 150,000 Chinese Nationalist soldiers, consisting mainly of poor peasants, arrive in Hanoi after looting Vietnamese villages during their entire march down from China. They then proceed to loot Hanoi.
September 22, 1945 - In South Vietnam, 1400 French soldiers released by the British from former Japanese internment camps enter Saigon and go on a deadly rampage, attacking Viet Minh and killing innocent civilians including children, aided by French civilians who joined the rampage. An estimated 20,000 French civilians live in Saigon.
September 24, 1945 - In Saigon, Viet Minh successfully organize a general strike shutting down all commerce along with electricity and water supplies. In a suburb of Saigon, members of Binh Xuyen, a Vietnamese criminal organization, massacre 150 French and Eurasian civilians, including children.
September 26, 1945 - The first American death in Vietnam occurs, during the unrest in Saigon, as OSS officer Lt. Col. A. Peter Dewey is killed by Viet Minh guerrillas who mistook him for a French officer. Before his death, Dewey had filed a report on the deepening crisis in Vietnam, stating his opinion that the U.S. "ought to clear out of Southeast Asia."
[...]
It's a long and intricate history...
Cheers,
Scott.