Just an FYI to justify my East Asian Studies degree: the Emperor as God-on-Earth Shintoism is largely a creation of the Japanese government and elites, extending from the late Meiji era (i.e. a couple hundred years after genociding the Christians) into the military junta that was ended by WWII. Shinto previously existed in Japan as a set of diverse minor traditions and local legends, and would have been mostly unrecognizable as a religion prior to it being used as a founding myth to justify the new regime.

Looking at the reading list for the course I learned that in (almost a decade ago now), I think the source is probably W. Scott Morton, "Japan Its History and Culture", but don't quote me on that.

Fun historical trivia note: the Japanese constitution forbids government support of religious schools. The reason for this is late 19th-century American anti-Catholicism. How the heck did that happen? Well, Protestant nativists afraid that Irish & etc Catholics were going to breed quickly and overwhelm "real" Americans passed a series of so-called Blaine Amendments in American states (failing at the national level), which forbid giving money to sectarian schools with the express purpose of forbidding Catholics to fund their schools with tax dollars. Some genius in MacArthur's constitutional drafting committee copy/pasted one of them into the Japanese Constitution.

For additional potent irony, I'd lay even money on the Blaine Amendments being declared unconstitutional (in the US, obviously) within the next few years. They will then survive only in 21st century Japan, protecting it from 19th century Irish immigrants.