Returned mail?

Normally I find that when I send letters or packages from Japan to my family in the US, they arrive in about one week with trouble. However, nearly a month ago, I sent two cards to the US, and they still have not arrived. I know the postage was correct (I had them weighed and stamped at the post office), and I have a photo of the addressed envelopes (they were special handmade cards, and I took a picture in case I wanted to duplicate them in the future), so I know the address was correct as well.

My question is this - if there was something wrong about the address would the cards be returned to me in Japan? In the US, if mail is for some reason undeliverable, I know it nearly always gets returned to the sender; I am wondering if it typically works the same way in Japan. I am beginning to think maybe I forgot to write ''USA'' at the end of the address (I can't see that part of the envelope from my photo)

Normally I'd just send a new card, but, as I mentioned, these were handmade and rather special invitations for two relatives to be flowergirls in my wedding, so I am hoping the originals either show up at their home, or are returned to mine!

I am wondering if it typically works the same way in Japan.

Yes, that's how it's typically handled in Japan as well. I hope they turn up one way or another soon!