That usually follows knocking into a really crisp sharp newly formed edge on a gorgeous piece of exotic wood ........ or even just a new cut pine workpiece. Crisp is fine but a very gently softened edge speaks more subtly of good workmanship. You have to start with the really sharp edge but softening that edge can be as little as a quick swipe with a bit of sandpaper or a rub with an off cut to burnish but there are lots of ways to get the perfect edge on the finished workpiece.
http://www.finewoodworking.com/2011/07/ ... ak-an-edge