I don’t know about Schengen but that’s not correct for Japan. You can get a visa to visit Japan from an embassy in a country you’re not a resident or national of, there’s no requirement for the visa to be issued in your country of nationality (although some embassies may choose not to accept applications from non-residents or non-nationals).

The Japanese embassy and consulates in the US only accept applications from residents of the US.

E.g. the NYC consulate: https://www.ny.us.emb-japan.go.jp/itpr_en/visa00.html

> You may apply for a visa at this Consulate if you are currently residing within the area covered by this Consulate.

Schengen does not work like that. While you are supposed to apply from the country you are a resident in, if you have valid reasons you can apply from any other country. This is also frequently necessary (eg: traveller without fixed residence).

Well, just happening to be in a different country is not a "valid reason". Maybe for someone from the West it would be accepted, but not for the rest of us.

Also, "a traveler without a fixed residence" can get a non-immigrant visa for Schengen? I'm sorry but this just is not true if you're not a Westerner.

> Also, "a traveler without a fixed residence" can get a non-immigrant visa for Schengen? I'm sorry but this just is not true if you're not a Westerner.

If there is no doubt that you will leave and you can sustain yourself: sure.

Being abroad is already a huge challenge to proving you're going to leave. You're showing you don't have much tethering you to your country of origin.