A blade processing (e.g., sharpening) device includes two sets of overlapping edge processing rings Inner diameter surfaces of the edge processing rings define a notch suitable for effectively processing a blade with a convex cutting edge profile. Certain types of edge processing rings are movable relative to one another to adjust an edge processing angle of the notch. Certain types of blade processing devices also can also process blades with concave cutting edge profiles. The rings may be contained at least partially within a protective housing. A blade can be processed by inserting a blade through a blade insertion opening in the housing and into the notch while a handle of the blade remains outside the housing. By grasping the handle, the blade can be manually reciprocated within the notch during edge processing.