The flag of Vietnam, also known as the “red flag with yellow star” (cờ đỏ sao vàng), was designed in 1940 and used during an uprising against French rule in Cochinchina that year.
The Vietnamese flag was used by the Việt Minh, a communist-led organization created in 1941 to oppose Japanese occupation. At the end of World War II, Việt Minh leader Hồ Chí Minh proclaimed Vietnam independent and signed a decree on September 5, 1945 adopting the Việt Minh flag as the flag of the Democratic Republic of Vietnam. The DRV became the government of North Vietnam in 1954 following the Geneva Accords. The flag was modified on November 30, 1955 to make the edges of the star sharper. The red background was inspired by the flag of the communist party, which in turn honors the red flag of the Paris Commune of 1871. It symbolizes revolution and blood. The five-pointed yellow star represents the unity of workers, peasants, intellectuals, traders and soldiers in building socialism. Unti lSaigon was captured in 1975, South Vietnam used a yellow flag with three red stripes. The red flag of North Vietnam became the flag of a united Vietnam when the Socialist Republic of Vietnam was formed in 1976.
The flag of Vietnam has a red background with a five-pointed yellow star in the center. It was first used in the “Southern Uprising” (Nam Kỳ Khởi nghĩa) of November 23, 1940 against French rule in Cochinchina. Wikipedia