The shown marks are found on red-clay ceramic items, which sometimes have paint-covered bases. While the main mark (the impressed initial) is clear, the "STYLE" information in the circle is often applied so badly that the text "NR." underneath "STYLE" is either smudged or barely visible.

M120701a
Impressed initial "R" in a circle ...

M120701b
... plus a circle containing the text "STYLE NR." together with varying numbers.