I wasn’t aware of this particular type of knife but ran across it while watching a movie. And my interest was piqued. It is called a subhilt knife and it has an extra guard on it. That extra guard is a sort of finger lock. When you hold the knife you put your index finger in between those two guards. this prevents the knife from being pulled out of your hand. This next picture gives you an idea of that concept. I am not holding the knife firmly but the grip I have here gives you an idea of how you would have your index finger in there.
It is an interesting knife and something I have never made before. And it did pose some new blacksmithing challenges for me. In particular the addition of that sub hilt was a bit of a riddle. But it was a whole lot of fun figuring out how to do it. If you are interested in learning how to make a knife like this I have a complete video tutorial on my youtube channel here: How to Make a Subhilt knife.
And here is one more picture of the knife. This is during the build process. The knife is nowhere near done here but this picture gives you a bit of an idea on how this knife is made.