I have recently acquired a 20x20x4 cm (8 x 8 x 1.5 inch) plate or dish with a modern (English) Royal Satsuma mark. The plate is quite heavy--about 1.75 pounds. What is the origin of the Satsuma? Any other information about it?

(I am trying to post the pictures to a "photo filer" url. Hopefully, the link will work.)

Thanks!