This is a Japan-made straight sided baby feeding bowl or dish dating to the 1930s. It's 6-1/2 inches diameter 1-1/2 inches high. Around the green rim are printed numbers and the letters of the alphabet. Inside is an image of a blanket-wrapped baby cradled in a quarter moon, surrounded by light blue sky and darker blue stars. There are some dark sand specks from manufacture in the pottery and a small chip under the rim, visible mainly from the side or bottom but not at all noticeable when the plate is displayed upright on a stand or shelf. The back is marked with the number 520C in a circle and Made in Japan.
I have a different baby bowl listed in my shop with a similar baby in moon image. The bowl I'm selling is a Japan copy of the American made earlier bowl - this one has a decal center decoration instead of a painted one.
1930s Pottery Baby in Moon Childs ABC Feeding Bowl Dish