This is a 5 sided bowl made by Blue Danube in the Blue Onion pattern.  The bowls measures approx 7 1/2" across from point to flat side.  The sides of the bowl are reticulated or pierced.  It has the block rectangle mark on the back. 
 

Item is in excellent condition with no chips, nicks or cracks.  Please view the photos for a better description. I have other Blue Danube pieces listed and more coming!