In the immediate aftermath of Japan's defeat in
World War II, the United States-led
Allied Occupation of Japan issued directives legalizing labor unions, which were then protected by the new
Constitution of Japan promulgated in 1947. In the early postwar years, numerous labor unions formed in industries throughout Japan, many of which were under the influence of the
Japan Communist Party. However, in 1950, following the advent of the global
Cold War, and taking advantage of the sense of crisis precipitated by the sudden outbreak of the
Korean War, conservative Japanese government and business leaders launched, with the tacit approval of US Occupation authorities, a "
Red Purge" to remove communists and suspected communists from government and private-sector jobs. As part of the purge, Japanese conservatives fomented "democracy cells" within the established, Communist Party-dominated labor unions. As these unions collapsed amid the purge, the cells emerged and joined with some affiliates of the
Japanese Federation of Labour to form a new labor federation, the General Council of Trade Unions of Japan, or Sōhyō. ==Early militancy==