How do I get my birth certificate, etc?

I can't find my birth certificate.

I was born in Kyoto, to a Japanese national and an American, and they brought me to the U.S., if it matters.
I'm 18, and I've decided to move to Japan. The parent's are long gone now, and I speak fluent Japanese. I hear that the crime rate in Japan is a lot lower than here.

So I need to know how to get my birth certificate.
I assume I'll need a passport, but will I need a visa even with the dual citizenship?
If anyone wants to slap me for not bothering to keep track of... well, anything, go ahead. I can feel the headache from all the work I'm going to have to do. It's slowly creeping up on me.
Impending doom.

Anyhow, thanks for helping me out!

Oh, and is a really old passport okay to use if I get a new picture? It's from when I was a toddler, haven't used it since.

- There should be an expiry date on the old passport. Probably it was good for 5 years. So it's highly likely it has already expired. Probably that's the one your mom got you for traveling to the US with you.

- So you'd need to come to Japan using US passport and coming as Temporary Visitor Status for now; if you know which ward of Kyoto you were born in and registered with, you can go to the ward/city hall and ask for your own "koseki" (family register), or to be precise for your "koseki tohon" (official copy of your family register).

- Using that, you can apply for a new Japanese passport.

Apply for a passport or replacement birth certificate in US- requirements have changed!

1. It depends if your parents registered your birth or else you will have to request for for a copy of Koseki from the ward of your birth in Japan.
2. Do you have an SSN? If so they might have registered your birth and their marriage in US- then request for a marriage license (as evidence of citizenship)if you know the state they registered their marriage.

3. According to the new requirement: Beginning April 1, 2011, the U.S. Department of State will require the full names of the applicantfs parent(s) to be listed on all certified birth certificates to be considered as primary evidence of U.S. citizenship for all passport applicants, regardless of age. Certified birth certificates missing this information will not be acceptable as evidence of citizenship.

4. Please browse thoroughly:
http://travel.state.gov/passport/get/first/first_830.html#step1first

Good luck!

The good news is you have a birth cert.
If you have a US passport, then you have a ''birth abroad'' birth cert.
It costs $40USD thru the Dept of State.
If your birth is registered in Japan, you need your mothers family register.
I only mention this because the US Military has different rules for birth registeration, and your birth may not be registered in Japan. It is not a requirement to register births in Japan for US Forces stationed in Japan.
Good luck.