The chalked edge blades sparring shows cuts and stabs. This is the easiest way to see if you would survive an encounter. The other is just zapping each other for fun.
I’ve trained force on force with a Shock Knife, and it’s a great tool.
But one of my favorite ways to train that with a knife is really simple:
-Nok Knife (look it up if you’re not familiar, you need one)
-Fire engine red lipstick
-Sterile white t-shirt
Generously apply lipstick to the blade edge, and start sparring. You start with your knife stored in a similar way that you carry it. Work on slashing because thrust are dangerous even with a knock knife. Eye pro is a necessity. Keep it moderated, and WHEN you get cut (if is non existent), work a tourniquet into it or other needed life saving measures.
The round ends really quick after someone engages, because you’re both going to bleed pretty quick.
Have someone on the sidelines with a red liquid in a spray bottle, simulating arterial spray.
And if you do it right and evade, gain distance / cover, and integrate some work with your holster with a SIRT gun or trainer. Bonus points if it’s covered in maple syrup (that’s the closest thing I’ve found to blood for training).
Strip mall karate and “I trained watching YouTube” is quickly exposed for what it is. Folks immediately reassess their gear setup and you no longer have to explain why you should always carry a TQ and knife fighting sucks.