Comment by dragonwriter
2 days ago
> Born and raised in Japan and Japan won't give him citizenship?
Unrestricted jus soli (extending nationality unconditionally to those born in the territory of the state, regardless of ancestry) is largely an American (as in "of the Americas", not merely "of the United States of America", though the latter is a significant reason why it is true of the former) thing, though there are a few countries outside of the Americas who do it as well.
Some more countries have restricted jus soli, extended to those born in the territory of the state only if the government judges them to be ineligible for nationality by the law of any other state, or perhaps only if the parents are actually stateless, as a way to mitigate statelessness. (And states who have adopted a rule of this type for this purpose may have done so after the UN Convention on stateless persons in 1954, and may not have applied it retroactively.)
Unconditional jus soli is rare, but a lot of countries have a good approximation of that for a practical reason -- to not have the administrative burden of dealing with people who already live there, participate in the society, pay taxes and all that, but don't get the right papers.
It varies a lot. It does happen that people are refused citizen ship of, even expelled from, the country they were born and grew up in many countries. It is not common, but it does happen.