Japanese post-war history
https://www.japan-guide.com/e/e2124.html
This page, intended for visitors to Japan, offers a brief and clear summary of the effects of World War II on the country. Even for those who are visiting only via fiction, this is a quick and useful way to understand the scope and effects of American occupation on 1940s Japan.
A Fresh Look at the Lives of Japanese During World War II
https://www.pomona.edu/news/2016/02/10-fresh-look-lives-japanese-during-world-war-ii
This page summarizes some of the research of Samuel Yamashita, who has examined primary sources, such as diaries and letters, written by Japanese citizens during World War II. The article gives a sense of the war's emotional effects and of the various political ideologies at play during the time period.
Occupation and Reconstruction of Japan, 1945–52
https://history.state.gov/milestones/1945-1952/japan-reconstruction
This article, published by the U.S. State Department, gives a slightly more detailed summary of the American occupation of Japan, albeit one from the perspective of the American government. It focuses particularly on economic factors and on the international political context of communism, the Korean War, and the Cold War.