Small Flambe Glaze Stoneware Bowl, Rough Rim

I am not sure what that it, how old nor where it came from. A wild guess would be an Asian brush washer.
I wonder why the rim is so rough and chipped?
I don't think that it was damaged with the time as there are glaze drops on it. I assume the piece was fired upside down because of its shape and there are no spur marks. Also, surprised that the glaze did not run but stops short of the rim.
The only thing I can think of is that the rim stuck to the kiln shelf and had to be knocked off. But that usually is the case with runny glaze. Why would the bisque stuck to the shelf?
Any thoughts?
Thanks

 

Hi,
Looks like a piece of Raku.
greg

 

To me it looks like high fired glaze rather than raku.