The person wielding the knife usually is quite confident and focused in using in his weapon. I still have to see someone stabbing with one hand and punch with the other. Of course nothing will ever be 100% sure, but better some cuts in the arm than holes in your torso.But I still have to see a knife defense that is more simple and has a rate of sucess higher than this one.
You still don't get what i was trying to insinuate.
Plain and simple.
You block like that with someone who has 5minutes of knife training and they'll staple that arm to your torso using the knife. = arm messed up, but more importantly lungs/heart/neck perforated many times with 9" kitchen knife.
Your best case scenario-
I have the knife, you attack me with your fist and I get a broken nose, cut mouth or even a broken jaw. Simutaneously with your punch you rising block or attacking block my knife hand. I ice pick stab. You block, fortunately for you I have the blade out, so my knife doesn't slice down your wrist to your elbow joint.
Then what do you do?
Likely scenario-
Blade out. Knifer is over confident, and in a primal state, jacked on adrenaline if not drugs as well. You seeing he has an ice pick grip like you've worked in Krav. You remember the drill in Krav. He attacks, knife in the lead, you overhead block and punch slide to get the under hook on his knife arm and head control. Your punch hurts, but has minimal effect. The knife is coming down and slides down your arm. You knee him in the groin. He's on top of you, he stabs again, this time it hits you in the upper chest penetrating your lung. Feeling like a hard punch. Your arms are trying to block. Your arm comes up to block the knife hand, successfully meeting his wrist. The blade a kitchen knife is 9" long, only 4" penetrates your chest this time cause you blocked.
His knife knocks you back. You think you're doing ok cause you feel only hard thuds on your body and you landed your punch to his face and knee to his groin. He strikes again, and again and again. You keep blocking and hitting him, trying to work that modified thai clinch of underhook head control. How many can you block? How many of those blocks are still letting the knife through?
Worst case scenario?
He has had training and he has knifed meat in the past. He knows how to choose a blade. He knows how to use a blade. He knows there are only a limited number of ways to defend, he anticipates those into his flurry. You block, he pins your arm to your waist and knifes you till you drop, follows you to the ground and keeps knifing you till see black.
The second part is my point as well. You have just begun your martial arts journey, there is more than Krav Maga.
The video here says the 'Chief KM' of the US.
YouTube - Krav Maga: Knife Defence 1
same series heres the ice pick @ 2:30
YouTube - Krav Maga: Knife Defence 2
^ I seriously want you to find a recreational mma friend and you give them a rubber/soft knife. Have them wear a cup/mouthpiece, mma gloves and come at you ice pick style with the knife. I'll play handicap and for the attacker to win he must land 3 ice pick thursts to the face/neck/torso. Tell us if you 'survive' those attacks.