vintage lithophane porcelain sake cups, Japan Geisha girl under bubble glass

Set of five tiny cups or dishes (sake glasses?), lithophane porcelain. We're never seen any lithophane wares like this before.

They have a domed round convex glass 'bubble' in the bottom of the cup bowls, and the Geisha image in the china can clearly be seen through that. It was very difficult to get clear photos of the lady, it's much clearer in real life!

The cups are about 1 5/8" tall x 2" in diameter across the bowls. Four look very good, one has a tiny brown hairline as shown. Label is Lida's - Japan.