I have had a couple of Welz pieces in this shape, one is pictured in orange here, and the other was lost in my shelving collapse last year. This was purchased from a friend in Arkansas.
Although unmarked the shape is the same as the orange example which has a telltale applied rim decor and no pontil mark. In addition the orange example also has the small font, single line "Made In Czechoslovakia" acid stamp on the underside. Although I do not consider the mark to be a "Welz" mark as such, it is typical of many examples of Welz that are found with the acid stamped provenance mark.
This new example in blue and white stands at 8 inches tall, 4.25 inches i diameter at the rim which has 6 ruffles, and 3.5 inches in diameter at the base. These measurements and details are the same as other examples of Welz in this shape.
Obviously the mark dates the production to the interwar period, and I have not seen this decor before on any shape.
Craig