I stand to be corrected on this! Saw back knives have been around for hundreds of years. They were originally used to cut grooves and notches in bones, antlers and other hard substances that the cutting edge of the knife could not cut.<br><br>The purpose; grooves allow you to secure sinew or rope to an improvised implement so that the sinew or rope doesn't slip off.<br><br>Antler and bone makes the best improvised snow goggles, fish lures and hooks, harpoons, spear heads and kakivaks( forked fish spears). All of which need to be secured and not allowed to slip. <br><br>Mariner.<br><br><br><br>