The Japanese Self-Defense Force, also known as the JSDF, and JDF, started in 1954. The Japanese Self-Defense Force is controlled by Japan's Ministry of Defense. After World War II in the 1940s, Japan's military was cut severely. Treaty of Mutual Cooperation and Security between the United States and Japan was signed in 1952 and led to the activation of the Japanese Self-Defense Force. This treaty was signed during the Korean War amid fear of communism spreading in Asia.