Antimonopoly Act (Japan)

Japanese competition law consists of the Antimonopoly Act (独占禁止法, Dokusen Kinshihō^?, "AMA"), officially the Act on Prohibition of Private Monopolization and Maintenance of Fair Trade (私的独占の禁止及び公正取引の確保に関する法律, Shiteki-dokusen no Kinshi oyobi Kōseitorihiki no Kakuho ni Kansuru Hōritsu^?, Act No. 54 of April 14, 1947), and several other statutory laws.

The AMA was introduced during the postwar Allied occupation. The U.S. Government, on 6 September 1945, issued a presidential directive instructing the Supreme Commander of the Allied Powers (SCAP) to dissolve Zaibatsu structures. Prior to World War II, Japan had no antitrust laws. There were seventeen Zaibatsu organisations, the four largest of which had controlled approximately a fourth of all of the paid-up capital in the Japanese economy just prior to the World War.

In opposition to General MacArthur's fear that Zaibatsu dissolution would lead to instability, the U.S. Departments of State and Justice sent a "Special Mission on Japanese Combines" to Japan for the implementation of a comprehensive antimonopoly framework. In response, MacArthur coerced the Japanese Diet into adopting legislation known as the Antimonopoly Act (AMA), with the persuasion to them that enforcement was optional.

...
Wikipedia