Koseki, Duel Citizenship and Inheritence Laws

Hi I haven't been able to get a clear answer from anyone not even my Consulate about the following question.
My father was a Japanese citizen when my sister an I were born in the US to an American mother. He added us to the family Koseki in Tokyo, Japan. A few years later he became a US citizen. Neither my sister or myself have obtained a Japanese passport. We always visited Japan with a US passport and have considered ourselves US citizens all our lives. When I turned 22 (I am now 26 and married to a US citizen) I assumed my Japanese citizenship would just be erased if I didnt declare myself a Japanese citizen.
My father passed away a few years ago from cancer and we always assumed our duel citizenship situation was handled. He was our only link to communication with family in Japan. This summer my untrustworthy non blood related uncle who lives in Japan with my Aunt and Grandmother told us that we need to formally renounce our Japanese citizenship immediately to be "good" law abiding citizens. I dont speak Japanese and my uncle is barely understandable but he says my Grandmother saw me and my sisters name still on the family koseki and she wants us to renounce our citizenship to be good law abiding Japanese citizens.
We are no where near the appropriate consulates to do the formal interview so it will take some time. My uncle has been sending emails everyday saying that we need to do this immediately to make my grandmother happy. I am suspicious that he is trying to push me and my sister out of any inheritance we may be granted when my grandmother passes. The Japanese Consulates I have contacted see no need to do this interview process and do not understand why family in Japan would want us to do this since my sister and I have always and will always be US citizens.
So I guess my point is, are there any legal repercussions from having our names removed from the koseki in relation to Japanese inheritance laws? I just dont trust that my uncle truly has our best thoughts in mind. I dont even know if my Grandmother knows what he is saying to us.
Thank you soo much for any helpful advice!!!

Why are you listening to a man you know is untrustworthy?

There is absolutely zero you "need" to do about this or the Japanese government would have contacted you.

Yes, that will affect inheritance even if not directly. To get inheritance you need to prove who you are, and the koseki, as far as I know, would be a large part of that proof. One thing Japan is really bad at is options and alternatives. They always, ALWAYS go for the magic bullet and the one-size-fits-all-shoe. They will trust the koseki sooner than a DNA test, assuming they would even discuss a DNA test. Its whacky.

Also, as far as I know, the koseki has ZERO to do with citizenship. I am married to a Japanese and on her koseki, but I am not even a permanent resident.

Basically what I would do is tell your uncle to cough up some official documentation proving his words. After all, is he a lawyer? Just tell him he is incorrect and if he thinks different, he needs to prove it. Its his contention, its his homework, not yours.

Good luck with the inheritance in any case. My experience is that laws and rules aside, those not there on the spot always get ripped off. Odds are good you won't even be informed of anything until well after the funeral is over unless there is someone in the family you can trust to get you the information. Either that or you need to find out who is going to be executor of the will, pray its a lawyer, and get that lawyer's information and attention before anything goes down.

But looking at your post, I am going to guess you won't have the strength of will to get the information you need.

As far as dual citizenship goes, neither country does that officially. What that means is that its technically not allowed, but since they overlook it or don't have the means to enforce it, it is possible in the real world. If they ask for your passport, you just give it to them. Go to your other embassy and get a new one. Of course this requires a lot of lying, like saying you renounce one citizenship and not mean it all, like Chris Savoie. But at this stage, I would be surprised if Japan would give you a passport, and if they won't, you aren't a citizen.

My opinion to your question is the same as Mark's, and my reaction to your inquiry to the consulate is the same as what the Consulate had told you. I don't see any problem leaving the things the way it is now, from the standpoint of you and your sister. Under Japan's nationality law today, foreign nationals are mentioned in the koseki if they are related to or married to a Japanese citizen.

You can leave the koseki untouched for now unless your uncle comes up with a rightful reason for doing so, along with legal evidence supporting it. If I had been asked that, I will feel that the uncle wants you out of the koseki to remove you as rightful heirs over inheritance matters.

Hope it helps!

Well, I have to disagree with Mark of Zoro on the inheritance part. Lets say you do get taken off that Koseki, it does not affect your ability to get inheritance, it just means you are not on the same Koseki. Normally here, when you are removed from the Koseki, you will either go onto someone else, if under 20 years old or you will make your own if you are over 20 years old. The fact remains that you are blood family and no Koseki can change that.

And be aware that if you do get removed from that Koseki, you cannot go back on it. And being that it is not your uncles Koseki, but your fathers, he has no legal right to do anything.

Also regarding your dual citizenship, there is nothing in criminal law here that will affect you for having dual citezenships. Generally speaking, when living in Japan the government requires you to choose a citezenship when you turn 25, but all of the people I know with dual citizenship have not informed the government and no one is the wiser. The government does has the right to take your Japanese citizenship if you refuse to give up your American one. But, that still does not remove you from the Koseki.

I honestly don't see a reason why your grandmother would want any of you off the Koseki, when it means so little with your father now passed away.