Im not sure if this is Japanese or Chinese, the shape looks more Chinese than Japanese but the dragon looks like similar Japanese 3 claw dragons that I have seen in the past, this appears to be old and dose not seem to have the same ring when I klick it with my finger as some of the late Qing that has a little higher ring, it is porcelain but not as refined, and it has rust spots, pitting and medium to large bubbles in the glaze also what looks like blisters in the blue, if this is Japanese it could be 18th century all viewers are welcome, the blue color is right for 18th century.
Here are more photo's, thanks for viewing.
Stan, this is Chinese...a Yuan style blue and white Yuhu Chunping. This one has the typical Yuan dragon with three claws.
B/W wares were developed in the Yuan dynasty and are considered rare. I do not think it is of the period, though, but would hang on to it. The chance of getting an authentic one is small. Mostly they are newer, 20th century copies what we see.
Still, better try to find a specialist on Yuan wares to make sure. Even experts often do not know enough to authenticate them.
Yuan blue and white wares were only rediscovered in the early 20th century, after knowledge about their existence had disappeared in the Ming dynasty, so rare were they. It seems that even the Qing government had no knowledge about their existence.
Thanks Peter, thats great, Im glad it is Chinese that is.