What is the history of Vietnam prior to 1954?
It was a French colony.
There is no "North Vietnam" as a country. The term "North Vietnam" was an erronous term used by the US to justify there intervention into Vietnam after the Paris Peace Accord 1954 which temporarily divide the country into 2 parts, North and South. FoIn the history there was no north or south country in Vietnam. The capital of Vietnam is Hanoi.
Prior to 1954, there was no North and South Vietnam. It was a single unified country called Vietnam. Unfortunately, it had been under foreign control since 1858 when the French invaded and remained to occupy. Prior to World War 2, Japan invaded Vietnam and forced the French to leave. The American allies promised Vietnam that if they aided the allies against the Japanese, they would be awarded with independence after the war. Although they did…
Drop in zone. Inasmuch as your question is in the War and Military History section, specifically Vietnam, I am assuming you mean D "M" Z, not D "N" Z. DMZ means Demilitarized Zone and in the case of Vietnam, it refers to the line drawn at the Geneva Convention in 1954 that divided North Vietnam from South Vietnam.