Schwarzenbach
"Schwarzenbach an der Saale" is the name of a town in Bavaria, Germany.
"Schwarzenbach" was the commonly known name or brand used for the porcelain produced by "Porzellanfabrik Oscar Schaller".
"Porzellanfabrik Oscar Schaller" was established in 1892 by Oscar Schaller. And later(c.1950) the company merged with Porzellanfablik Gebrüder Winterling.
The other source: Founded in 1905.
Ref.: Eschenbach
Oscar Schaller Marks
c.1918 ~ 1935
1935 ~ 50
1949 ~
c.1950 ~
Since the period when East and West Germany were separated was from 1949 to 1990, we can assume that the product that has "Western Germany" was produced during this period.
Winterling Marks
c.1950 ~