Renewing my Japanese passport

Hello!

I am a 21 year old Japanese American, born and raised in NY. I am still both a Japanese citizen and an American citizen. I'm trying to renew my Japanese passport in NY, (which expired 5- 10 years ago) while retaining my American citizenship. I am trying to move to Japan for work. From what I could find so far, a lot of posts made on this topic are old and most likely outdated. I understand that Japan does not allow dual citizenship, but I also heard it is also in a gray zone where they will not force you to renounce one of your citizenships if you so choose.
Is there any possibility I can renew my passport and move to Japan without the need of getting a visa?

Sure, just go to te embassy, say you are a Japanese citizen and you want to renew your passport. Simple as that.

As Firas said.

I sent you a private message with some additional information and advice, if you are interested in reading it.

ask your Japanese parent how to get the passport. (how the system works)
your old passport was expired. I think you have to have a new one from the beginning. you need to take full paperwork.
the Japan embassy in US will help you, if you can give them enough information.
do you know your permanent address (where your Koseki is) ?

The law just says you should choose your nationality before you reach the age of 22, so if you're still 21 there is no problem whatsoever upon renewing your passport.
http://www.moj.go.jp/MINJI/minji06.html

Thank you very much for the help everyone, I will go to the embassy to have it renewed!