Round Vase With Intriguing Signature

This ceramic vase, 5" high and 5" at its widest, is gray, with a dark brown and medium blue hand-painted design of stylized flowers and vines. The finish is high gloss with a fine crazing throughout. Here's what I found intriguing: The signature on the bottom has a rather professional look. It appears to be a W superimposed on a V, or vice versa. In addition, it seems to say "No 4," as in "number 4," I suppose. I've searched and searched but been unable to identify the signature or where the "No 4" might come from. Has anyone ever seen similar markings before? Thanks for any help my fellow collectors can offer.