Japan is somewhat of a freak connoisseur of popular media, especially that which originated in or grew to be popular in his country. As such, it's likely that he'd recognize most of the anime/manga and video game characters here (along with some of the movie people). He's a polite man, so he won't necessarily break 4th wall with anyone without permission, but as a player, I do need to know if you'd want your character to be recognized or not.
Characters from different canons can have different answers. I'll just explain it away as Japan being old and forgetting stuff.
Example:
Mun name: Awesomesauce
Character name: The Name! (
usernamehere)
Canon: Official name of your character's canon so I can research; please don't abbreviate because I'm dumb and won't know what's going on ; ;
Recognition: Is it okay for Japan to recognize your character? Yes/No
Fourth Wall: Is it okay for Japan to fourth wall your character? If this is a maybe, please leave contact information (a link or your preferred method of contact) so I can get in touch with you.
Mun name:Character name: (
)
Canon:
Recognition: Yes/No
Fourth Wall: Yes/No/Maybe