Question

why was vietnamese divided after Independence?

Answer 1

After World War II and the collapse of Vietnam's monarchy, France attempted to re-establish its colonial rule but was ultimately defeated in the First Indochina War. The Geneva Accords in 1954 partitioned the country temporarily in two with a promise of democratic elections in 1956 to reunite the country. However, the United States and South Vietnam insisted on United Nations supervision of any election to prevent fraud, which the Soviet Union and North Vietnam refused. North and South Vietnam therefore remained divided until The Vietnam War ended with the Fall of Saigon in 1975.

After reunification in 1975, the newly reunified Vietnam faced many difficulties including internal repression and isolation from the international community due to the Cold War, Vietnamese invasion of Cambodia and an American economic embargo.[1] In 1986, the Communist Party of Vietnam changed its economic policy and began a series of reforms to the private sector and to the economy through what is known as Đổi mới, a political movement primarily led by Prime Minister Võ Văn Kiệt. During the 6th National Congress of the Communist Party of Vietnam, the country abolished its planned economy system in favor of a market oriented one. Ever since the reforms in the mid-1980s, Vietnam has enjoyed substantial economic growth.

Answer 2

the North was communist the South was capitalist which was determined by their supporter states the USSR and the US after independent in 1954 however this division was only meant to be temporary with election to re-unify the country.
during the Nguyen dynasty the Nguyen agreed to leave half of Vietnam to the French South Vietnam's ownership was transferred to US,and communist government tried to take Over south Vietnam which they successfully did.