1940 to '45.
China, France, Japan; in that order.
Japan
The countries that controlled Vietnam were Japan and France.
Japan .
China, France, Japan; in that order.
China, Phillipines, Vietnam
North Vietnam was controlled by communists.
Vietnam. NOT France.
During World War II, Japan controlled the Northern Marianas including Guam, Cambodia, Korea, Laos, Vietnam, and part of China. They wanted to control them-and they did.
France took over Vietnam 1895 and lost control to Germany when France was invaded by Germany in WWII. Germany then transferred control of Vietnam to Japan, their ally at the time. Even though Japan ruled Vietnam, French colonial rulers kept their power and were overseen by the Japanese. The Japanese did not have nearly enough manpower to rule Vietnam. When Japan surrendered in 1945, French colonial rulers attempted a rebellion against the Japanese, but were crushed. Many of the French fled or were imprisoned. The Japanese rule was very weak and was taken over by the Viet Minh (Vietnamese nationalist group) in the same year. The French wanted to retake control of Vietnam and started negotiations with the Viet Minh. All talks failed and war was declared the following year. This war is famously known as The First Indochina War. After many years the French lost and Vietnam was independent. Vietnam's rulers: 1895-1940 France, 1940-1945 Japan, 1945-1954 Vietnam independent, but warring with French over control.
When France left Vietnam in 1954 part of the country was controlled by the communists, and part was democratically controlled. The Communist controlled are became North Vietnam, and the Democratic area became South Vietnam.
During World War II, Vietnam was primarily controlled by Japan. The Japanese occupied Vietnam in 1940, taking over from French colonial rule. This occupation lasted until Japan's defeat in 1945, when the country was briefly liberated from Japanese control, leading to a power struggle that eventually contributed to the First Indochina War.