Interestingly, it seems that Japan does have a procedure for foreigners to officially adopt a Japanese name. Changing your name is often very hard, and doing it in a country where you're not a citizen might be completely impossible, depending on the country.
> Japan does have a procedure for foreigners to officially adopt a Japanese name.
Sort of but not really. The post-2012 residence cards do not display a registered alias anywhere, and since those cards are what banks are required to KYC you on, a lot of banks won't allow you to use a registered alias which in turn means it's hard to use it for anything else (credit cards, phone, pension...). It's very non-joined-up government.
