It looks like a Kangxi Plate. It has some cracks and rust. Can it date from the 17th Century or is it a modern replica?
Sorry for the quality of the last photo.
Another photo of the bottom. How much does a repaired crack like this affect the value of a plate?
A picture showing the foot rim shape, taken at an angle, may help.
I have heard that some restored items have a value of only 25-35%, but that is also dependent on rarity and type of item, of course.