Thats why you don't lead with the knife.
I read an interesting treatise on knife fighting done by Don Pentecost with techniques used by inmates in Folsum prison. Basically the jist was to lead with the offhand to tie up your opponent while keeping the knife hand tucked low and tight against the body, making quick rapid thrusts only when the opponent was already grappling with your offhand.
Oh I would never use my knife in a fight unless it was the last option. I have no training nor do I really desire to, that is what my CC permit is for.
I am going to have to agree with this. My Aikido training was many years ago, but I still recognize the techniques in the video. That being said, most knife fights tend to be pulling the victim with the free hand and using the knife overhand in their back. Aikido is probably very effective against two handed long blade attacks (ie. with a bokken) but probably is not a great system to defend against short blades in a single hand.
I refrained from posting, but seeing as there are like minds and experience, I will.
Spetsnaz has some good stuff, but there's some apparently telling demonstration in this video which happens a lot in MA. Predisposition to a prescribed outcome. Here, take this knife and attack me like this so I can show you that...
I love the Krav Maga handgun disarms too. Not that they don't work, or wouldn't... My point is this. Train with a live round in the chamber, and or attack with a real knife from someone not in your group. I could assure you, my blade will hits its target with this guy. And I'm nobody... And if anyone knows, has seen, or been in a real knife fight, attackers don't just lunge in with one overly committed strike. A Filipino would destroy this guy, Kali and others.
Knife confrontations -- always move, keep moving - or put space between you & your opponent. Grip is important - imagine trying to hold onto a double barreled .454 Casull derringer, while firing both barrels GRIP the knife THAT TIGHTLY. Read Hank Reinhardt's book.