can you find a forwarding address?

Hi,
I'm trying to find someone with an old address and a name. I know that they no longer live at the address and i'm wondering if I can obtain a forwarding address from the post office? Do they give out that sort of information? if so, whom would they give it to?

All you can try is to write to that person at the address you have, and see if that letter makes it to the recipient. The post office will forward letters to the forwarding address specified for a certain period, but it is not in their power to give you the address.

You can write to the address you have, and be sure to write your name/address on the envelope/card, so that in case that person did not leave a forwarding address the letter will be returned to you with a note to that extent so that you know.

i'm wondering if I can obtain a forwarding address from the post office? Do they give out that sort of information?

The answer is "no."
You can do is to try to send a mail in a way explained by AK.

Japan Post Service may forward mails during one year since the new address is notified through its branch or a post office.
To make that happen, a notification to the mayor of the change of addresses is not enough; a customer has to inform Japan Post Service on a paper in a certain format.

Thanks for you help, I fear sending a letter will not help because I am trying to send legal documents by certified mail. It sure is hard to find somebody in Japan if they aren't willing to help!

So you are not trying to send a letter and hear back from that person, but to "serve" a legal document?

Even if it is a certified mail, the post office will either forward it (provided the recipient left a forwarding address with them, and provided that it's within the specified period), or return it to you, so you will know for sure if you've reached them or not.

Upon a few internet searches, the rule seems to be that post offices do not give out the new address to anyone (not even to a family member living away) UNLESS it is by a court order. I don't know your circumstances, sorry about the lack of help, I hope things work out.