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No. You need a rubbing stone (usually a small piece of another coticule) but they usually come with the coticule (not in my case).

If the grits are comparable (a big "if" lol) then it won't make a difference. The reason I like Norton so much is because it cuts quickly and gets my edges up to snuff in no time, which is more than...

The Belgian blue is just a slow cutter. I'd use the Norton to get the blade shave ready and polish it off with a few strokes on the yellow. Blue makes a nice surface for it to stand on :D