A period known as Occupied Japan followed after the war largely spearheaded by United States General of the Army Douglas McArthur to revise the Japanese constitution and de-militarize Japan. The American occupation, with economic and political assistance, continued well into the 1950s. After the dissolution of the Empire of Japan, Japan adopted a parliamentary-based political system, while the Emperor changed to symbolic status.

American General of the Army Douglas MacArthur later commended the new Japanese government that he helped established and the new Japanese period when he was about to send the American forces to the Korean War:

The Japanese people, since the war, have undergone the greatest reformation recorded in modern history. With a commendable will, eagerness to learn, and marked capacity to understand, they have, from the ashes left in war's wake, erected in Japan an edifice dedicated to the supremacy of individual liberty and personal dignity; and in the ensuing process there has been created a truly representative government committed to the advance of political morality, freedom of economic enterprise, and social justice. Politically, economically, and socially Japan is now abreast of many free nations of the earth and will not again fail the universal trust... I sent all four of our occupation divisions to the Korean battlefront without the slightest qualms as to the effect of the resulting power vacuum upon Japan. The results fully justified my faith. I know of no nation more serene, orderly, and industrious, nor in which higher hopes can be entertained for future constructive service in the advance of the human race.

For historian John W. Dower, however,

"In retrospect, apart from the military officer corps, the purge of alleged militarists and ultranationalists that was conducted under the Occupation had relatively small impact on the long-term composition of men of influence in the public and private sectors. The purge initially brought new blood into the political parties, but this was offset by the return of huge numbers of formerly purged conservative politicians to national as well as local politics in the early 1950s. In the bureaucracy, the purge was negligible from the outset (...) In the economic sector, the purge similarly was only mildly disruptive, affecting less than sixteen hundred individuals spread among some four hundred companies. Everywhere one looks, the corridors of power in postwar Japan are crowded with men whose talents had already been recognized during the war years, and who found the same talents highly prized in the "new" Japan."

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