It's a different twist on alternative histories in which the Axis wins, or at least draws, World War II. Robert Harris's Fatherland envisions a different sort of Cold War, in which German ingenuity knocks England and the western Soviet Union out before the New World mobilizes, and Star Trek's "The City on the Edge of Forever" turns on the death of an American pacifist who Captain Kirk takes a shine to. The critical death in High Castle is ... not Anton Cermak. (The link contains a spoiler.)
But after the war, residents of the Japanese-occupied Western United States take to an ancient Chinese oracle, and there's a resident of the neutral mountain states whose subversive book, about the war turning out more like it really did, makes for the plot and character development. Or does it?
(Cross-posted to Cold Spring Shops.)