Very interesting about Japan!

To be clear, I wasn't thinking about within a specific country though.

More like, what is the set of all characters that are allowed in legal names across the world?

You know, to eliminate things like emoji, mathematical symbols, and so forth.

Ah, I see.

I don't know, but I would bet that the sum of all corner cases and exceptions in the world would make it pretty hard to confidently eliminate any "obvious" characters.

From a technical standpoint, unicode emojis are probably safe to exclude, but on the other hand, some scripts like Chinese characters are fundamentally pictograms, which is semantically not so different than an emoji.

Maybe after centuries of evolution we will end up with a legit universal language based on emojis, and people named with it.