Thank you for sending additional photos. I appears to be a chinese light celadon plate, painted in blue and light iron-rust with a dragon chasing a flaming pearl, marked at the back with the Yongzheng six character seal mark 大清雍正年制. It is a beautiful plate, but the quality of the drawing is not perfect and the "Da" 大 character with the rounded shoulder is odd.
My educated guess would be that this is a quality republic period reproduction. The light damage on the inside foot rim might have been intentionally done to get the plate through chinese customs. Well, congratulations, this is a quality piece of chinese porcelain.