Reverse Course was a change in US government and Allied Occupation policy toward Japan during the post-World War II reconstruction. Beginning roughly between 1947 and 1948, it lasted until the end of the occupation in 1952.
The impetus for the Reverse Course divides between global events and developments within Japan. On the one hand, it is linked to the escalation of the Cold War, the Chinese Communist Revolution and the looming Korean War. On the other hand, due to domestic inflation, the growth of poverty, and the expansion leftist parties, Japan seemed ripe for communism to both the Japanese government and the leaders of the occupation—especially to the leader of the occupation, Douglas MacArthur. The Reverse Course resembled Europe’s Marshall Plan.
The occupation had begun with various moves toward democratization, including land reform, the purge of officials responsible for Japan's ultra-nationalism, and the suppression of both the zaibatsu and the yakuza. This extended to Japan's new constitution, which included an article that barred the government from maintaining a standing army. This constitution and related policies had been written by Rooseveltian New-Dealers. The Reverse Course changed such policies in favor of the containment policy.
Reverse course Wikipedia
As a result of the Reverse Course, public-sector workers lost the right to strike, private-sector unions lost a great deal of bargaining power. Furthermore, severe blows were dealt to ideological freedom, to the zaibatsu-busting process, and to the suppression of the yakuza. It also allowed for the creation of the Japan Self Defense Forces. It put conservative politicians back in power, who went on to spearhead the development of Japan's Liberal Democratic Party. Opposition to the Reverse Course contributed to the protest against the 1960 Anpo treaty.
According to George F. Kennan's theory, Japan would serve as an industrial engine of East Asia; by extension, a strong Japanese economy would prevent communism from spreading in Asia. A remilitarized and strengthened Japan made Japan the cornerstone of US security policy in East Asia. As the US Dept. of State official history puts it "In this 'Reverse Course,' Supreme Commander of the Allied Powers, General Douglas MacArthur, focused on strengthening, not punishing, what would become a key cold war ally".