Manzanar is most widely known as the site of one of ten camps in the United States of America where over 110,000 Japanese Americans were forcibly removed during World War II from December 1942 to 1945.
General Onada is referred to as "Kakka", which translates to "Your Excellency".
Minister Tagomi sends General Onoda photographs of the effects of the atomic bomb in Washington: ruined buildings and radiation burns. These are actually pictures of the real destruction in Hiroshima, with some modifications.
Atomic bombs are called Heisenberg devices in the series. Named after Werner Heisenberg, a German theoretical physicist and one of the key pioneers of quantum mechanics. Because Hitler slowed research on the bomb he called "The Jewish bomb" the producers made it seem like an Aryan discovery to keep the story-line in line with Nazi victory.