Dual citizenship... to become Japanese

Hi! I've done some researches and read many of similar threads, but most helpful ones were kind of old so I'd like to ask this to make sure the information is still applicable, plus, I have a bit of a unique situation here as I am engaged.

I was born in the US to Japanese parents 26 years ago. I have been living here all my life but now, I really want to move to and live in Japan with my fiance (American) whom I plan to get married within a year.

My parents are separated and my mom currently lives alone in Japan. I visited her a couple of times with my US passport. My Japanese passport has been expired for over 15 years. As a note, I never chose either one of the citizenships like I was supposed to before turning 22.

My koseki (family registration) in Japan still exists, I should be able to obtain a Japanese passport with no problem. Is this true? And if I can obtain a Japanese passport, I will be able to exit US with my US passport and enter Japan with my Japanese passport? Then, they will treat me as a returning citizen? Would there be any problem since I've gone to Japan with my US passport only as recently as beginning of this year?

If it is easier, I am actually okay with losing my US citizenship. In that case, would I still have to obtain Japanese passport first and then file some documents in Japan? (in person?)

In short, I just want to legally say I am "Japanese citizen" and be able to stay in Japan for more than 90 days.


My next question is about marriage. My fiance and I both have plans about jobs in Japan but since they cannot support working visas, our solution was to get my future husband a spouse visa in Japan.

We have no idea how or if, even, the citizenships affect marriages.

First of all, we do want to have a ceremony (with an officiant) in the US as most of our guests reside here. Since we want to live in Japan after the wedding, I'd assume that I should sign the marriage license as a Japanese citizen...? Would renewed Japanese passport all I need to bring to prove my citizenship when we file the paperwork at the office? After the wedding, we will fly to Japan and complete their paperwork (kon-in todoke) to legally marry in Japan too... and then apply for spouse visa? -Oh, and we do understand that the spouse visa application process can be very long.

Is there any reason that we'd have to fly to Japan BEFORE the wedding? If there is a better, safer, or easier process, please tell me.


May not matter, but I have been dating my fiance for almost 10 years and he has been to Japan a few times. Also want to mention that we really understand that the life in Japan won't be just fun, or easy at all, but we will definitely regret if we don't try.


Thank you for your time and any kind of advice is much appreciated!

Your Japanese nationality is still valid after age of 22.
Japanese Govt is unable to delete and remove your nationality, therefore your JP nationality is still valid.
BUT, at the embassey/consulate general of JP, the staff will ask you why you didn't choose your JP nationality before turning age of 22. This is an enforceable rule. So it can be expected a negative argument there(it often happens).

About your marriage by nationality depends on you nationality at the time you get married. So it is unsure.

You can leave the US with your US passport and enter in Japan with your JP Passport. This is legal.

You can not renew your US passport after you got your JP nationality and passport.