For renewing a US Passport, Can you add a legal alias (通称) from Japan as one of the “additional names” in the form Ds82 line 9 (list all the other names you have used)?
If so I think I will go back to the city hall and ask for a receipt of when I officially registered my alias and make a translation of it, attaching it to the form, but if anyone has any experience/advice let me know. It’s not a legal name necessarily so if it won’t work I’d rather just forgo the process of course.
Best
by NB_Translator_EN-JP