Originally Posted by
gugi
I can give you an explanation. When you angle the razor, along with x-stroke you are effectively honing more 'along the edge', close to having the razor perpendicular to the hone and just pulling it across. Of course you're using primarily the edge of the hone to go along the bevel. The advantage of an angled razor with x-stroke vs. just pulling the razor perpendicular to the hone is that you move the edge across different sections of the hone i.e. fresh honing surface throughout the stroke.
The thing with curvature on the edge no matter if due to warp or smile is that you have to hone it one point at a time, as the hones are generally flat, and thus cannot be in contact with more than one point of the edge at the same time. That's just basic geometry.
So that angled x-stroke is the best solution to draw the whole razor's edge across the edge of the hone (the hone edge is the only thing that can do the the concave side).
I guess that may be more explanation than you wanted, but that's really why it works as well as it does.