Bill, I'm glad you posted those pictures. I've been collecting straights for many years and had always referred to that feature as a "Sheffield" notch. My friend and mentor who spread that dreaded disease on to me called it that, so I just carried on with the same name. I guess since I had only seen the notch on the older blades made in Sheffield, I never questioned the characterization. This more functional description offered in this thread makes more sense to me. I wonder if this is a regional term, or was my friend just "off base", as I have accused him of being about many things over the years.