I have an unmarked willow platter that I bought several years ago at a garage sale. It is medium to dark blue and a creamy white. It also has slight indentations on the corners and ends (8) The glaze is cracked. It is a transfer pattern and the pattern is slightly raised. The back is slightly stained and has what I call pock marks. Is there anyway I could date this piece or find out where it was made and by whom? I know very little about willow ware.