Vintage Hand Painted Coffee Cup Mug with a Chinese Makers Mark.   It may be Zhongguo Zhi Zao.   This mug holds 11 fl oz when filled to the brim.   All edges are smooth.   No scratches, nicks, chips, or cracks.     There are  a couple of tiny dots in the white, under glaze, with close up photos provided.   Shipping will be USPS Priority Mail .    Thank you.