I'd suggest Embracing Defeat: Japan in the Wake of World War II by John Dower.
Embracing Defeat tells the story of the transformation of Japan under American occupation after World War II. When Japan surrendered unconditionally to the Allied Forces in August 1945, it was exhausted; where America's Pacific combat lasted less than four years, Japan had been fighting for 15. Sixty percent of its urban area lay in ruins. The collapse of the authoritarian state enabled America's six-year occupation to set Japan in entirely new directions.
Because the victors had no linguistic or cultural access to the losers' society, they were obliged to govern indirectly. Gen. Douglas MacArthur decided at the outset to maintain the civil bureaucracy and the institution of the emperor: democracy would be imposed from above in what the author terms "Neocolonial Revolution." His description of the manipulation of public opinion, as a wedge was driven between the discredited militarists and Emperor Hirohito, is especially fascinating. Tojo, on trial for his life, was requested to take responsibility for the war and deflect it from the emperor; he did, and was hanged. Dower's analysis of popular Japanese culture of the period--songs, magazines, advertising, even jokes--is brilliant, and reflected in the book's 80 well-chosen photographs. With the same masterful control of voluminous material and clear writing that he gave us in War Without Mercy, the author paints a vivid picture of a society in extremis and reconstructs the extraordinary period during which America molded a traumatized country into a free-market democracy and bulwark against resurgent world communism.