How would this work? I don't get it.

But yeah. Checkers without the forced jump isn't checkers. I don't know WHAT you'd call it. Maybe "one-move diagonal chess," as without the forced jump checkers becomes akin to chess in that you can't force your opponent into anything like a shot, but rather if he is threatened he can retreat. Not to say moves can never be forced in chess or in whatever you'd call this guy's version of "checkers," but it's not the distinguishing characteristic of either the way it is in actual checkers.