Nippon collector plate

I don't know how to find out what this is worth or if its worth anything. I'm just trying to see if anyone knows who I can talk to about it. I've had it as long as I can remember but no clue how old it is really. I know it's Nippon and that's about all I know. I looked on their site because of the stamp on the back but haven't been able to find this plate. What do you think? What is it and is it authentic?