Foreign Passport Renunciation

I was born in Japan to a Japanese and foreign parent. I have been in the US for the last 20 years without leaving the country and have not renewed passports. At this stage in my life, I am ready to return home with my child.

My strategy is to renew my Japanese passport with declaration of intent to renounce second nationality upon arrival and to acquire a Dependent's Visa for my child.

I'm curious about what this process is like. Do you do this upon arrival at the airport? Is there any testing like when people seek to naturalize? I understand I'll need to acquire an insurance card. Somehow I need to establish banking and a Japanese credit score. What other type of paperwork is required? I want to know what to expect so I can be best prepared.

My Japanese is only at a JNLP 4 level at this time and I have every intention of studying to become totally proficient. Before I arrive back though, I think I should study vocabulary pertaining to this government process. Do you have any suggestions there?

Also, for more perspective – I have had very poor health and therefore financial status while in the US. I own no assets other than a small LLC which I'll be looking to offshore at some point. (Any advice around that?) I have filed my taxes every year and owe nothing to the IRS. I haven't made enough to owe. I do have some government debt in the form of small SBA and School Loans. So long as I continue to repay as agreed from overseas there should be no issue around my nationality change should there?

Any other advice is appreciated.

Thank you for your help!

by Beneficial_Chair_464