Help please - tortoiseshell bulbous pitcher

Hi,

I was wondering if anyone has any ideas of who this piece is by. Its stunning and the glaze is amazing.

Its 10inches tall and 8inches wide the glaze is almost tortoiseshell, a rich mix or brown, red and cream, the inside is all black.

Although it is huge it is not heavy and the bulbus edges are quite thin, when you tap it almost sounds like glass.

The makes mark on the bottom is either a W and 3 vertical lines or a 3 horizontal lines with the letter R beneath it, I'm more drawn to the R

Thank you Guys Emma TWB