some more Gintama musings - other Earth countries [spoilers]
Some thoughts on the Gintama worldbuilding, absolutely overthinking it for the fun of it.
We don't see or even hear much of other countries on Earth than Japan in the world of Gintama. They mostly seem to exist as places pop culture can come from (which means chiefly the US). The way the arrival of the Amanto affected them and how they tried to fight back and were defeated is never mentioned. It seems that Japan was the place that gave the Amanto the most trouble, due to the sturdy discipline of its samurai. (At least that's what the Japanese think themselves.) This seems rather doubtful if you look at RL technological levels in the 1850s - but to be fair we don't know that the arrival of the Amanto (plus, you know, the existence of the Altana) was the only difference to the real world. Maybe the industrial revolution started later in the world of Gintama, for instance. Maybe great plagues had swept across many of the world's countries (but not isolated Japan) and decimated populations. We don't know because we're never told.
The real answer is likely just that Sorachi wasn't interested in talking about the rest of the world, but he did imply the Tendôshû were particularly interested in Japan, and that the reason was the unusually powerful Altana vein right where they constructed the terminal. Perhaps the smaller openings of Altana across the country were unusually many (like natural hot springs??), or unusually accessible. Maybe, while the whole planet has untouched Altana resources, in most other countries you need to drill deep for it, while in Japan it's closer to the surface, hence much easier and cheaper to extradite? Plus there's that one extra-powerful vein right in Edo. So that's where they have the space terminal constructed - and that's the city and the country the Tendôshû pay the most attention to.
If that's so, what does it mean for the rest of Earth? Maybe both good and bad. The Tendôshû might not be as interested in meddling with the internal affairs of other countries as much as they are with Japan -- but they would still want them to be kept subjugated enough to make that costlier Altana mining possible, and to disallow those other countries to threaten their hold on Japan. And it does make me wonder if the Tendôshû might actually have been less brutal in Japan than they could have been - not that I think they care about human lives, but they might want to minimize chaos in that strategically important place.
If so, other countries in the world might have seen some great devastation during the invasion era, in the name of deterrence - easier to drop a few powerful bombs or let loose a few bioweapons than to having to go into finicky politics and keep an eye on various local factions. A sobering thought.
(Though presumably the US would be largely spared given that it produces a lot of the same cultural exports than in the real world.)
The use of the Enmi in the war in the second animated movie goes against the above reasoning: they imply that the Tendôshû would be happy to see every human dead, leaving the area vacant. Assuming we take the background of the second movie to be part of the wider canon, maybe after that plan had apparently failed, the Tendôshû decided to keep working with what they had instead. Especially since the Shogunate soon won the war anyway. Possibly it's very expensive to call in the Enmi...
