Featured MCM vase. W. Germany?

I have had this MCM vase for ages but know nothing about it. It looks West German to my layperson's eyes.

White and brown glaze, whitish clay. 15 cm high, ca 5.9".
Impressed code on the square base, but the glaze has filled the code, so rubbing cinnamon into it doesn't work. Maybe S906? 5906?
I hope someone can read it properly, and/or recognize the design and maker. Or one of our brilliant searchers can find a similar one. Goggle didn't want to help me today.

Thank you for looking.



Photos are a bit dark, the sky is overcast and there is a light drizzle. Not enough to help with the drought we're having. Ah well.

 

S 106, with a scratched 2 under this code?

 

Thanks Marote. I didn't even see the 2.

 

I just checked, it was a bit of dirt. It is gone now. (Did I destroy a rare and valuable masterpiece?)

 

Often German pottery numbers relate directly to the shape number and size. Not sure if this is help or hindrance