Adam, I put the notches in purely for historical decoration. I have heard many reasons for the notches from catching a blade in knife fights, working line (nets, fishline etc.) and also as a stopping point to sharpen. I really do not know. Maybe KHalverson will know. The file work on the backside gives me a place to put my thumb for more leverage, but you often will see file work on period hawks as well. I also would hate to think times were so bad I was knife fighting with a patch knife!