Help with dating a plate?

[bexxeb]

Hello, found this plate in my attic and of course have no idea on if its even chineese or how old it is. Have tried to look up the symbol on the back but cant even work out what it is? Any ideas or a point of direction would be much appreciated. 

[peterp]

This has a Chinese motif called "over-the-wall-dragon" because part of it is painted on the underside. However, several features do not look like a traditional Chinese item.
The shape is no Chinese shape. With a glazed bottom it would have a foot rim, here it is virtually flat. The clouds do not quite look Chinese either, and this mark is no Chinese mark. Not sure if this could be Vietnamese or Chinoiserie. Let's see if someone else recognizes it.