That's a strategy I've considered and practiced with my son - of course what works on a 10 year old has a great chance of not working on an adult, I haven't tried it against a large determined partner yet. My thought was if the attacker is keeping the knife hand to the rear and stabbing that if I could get control of the lead hand I could get them in a position where they couldn't reach me with the knife.
Have you tried that in practice yet?
Did a bit of experimentation with this a few weeks ago with one of my students and got some mixed results.
Now to be fair I am not a judo man or grappler , I am a Wing Chun man.
What we found is that the arm drag works great when his lead hand is already in contact with you , say for example on your chest , you can go pretty quickly from blocking the knife thrust straight into the arm drag and get around to his back , and what we did then was get a a hold of the arm and shoulder and start laying in repeated knee strikes to the back of his hamstrings.
When we tried it without the lead arm in contact range we found that while you were in the process of trying to capture the arm for the arm drag you would be gutted , it just took too long to get it on and in the mean time you would be getting stabbed.
Still keeping with the theory of trying to get around to his back , we used a different technique.
What we used was the Wing Chun pak sau , essentially a sideways slapping parry to the wrist of his lead hand.
It had the effect of knocking his arm sideways and putting his body in an off balanced position and gave us enough of a gap to step around at a 45 degree angle and get around to his back.
We practiced it with my back against the wall so I could not use my posture to get my hips back to avoid the knife thrusts , if his lead hand is coming forward almost at the same time as the knife thrusts commence , then I had to use three movements simultaneously.
I had to jam/deflect his knife thrust at the inside of his wrist with one arm , while I side parry his lead arm with the other .
At the same time I also did a low heel kick to his knee/ shin.
The low heel kick served two purposes , it stopped him from advancing and getting greater penetration with the knife hand , it also serves as a distraction , hopefully stunning him long enough for the time I need to step around and get to his back.
So to summarise , if it's close range and the attackers lead hand is already on me then I will use a two handed arm drag due to it's powerful displacement effect on the attackers body.
We used a two handed arm drag because in some instances he had a good hold of my shirt and the two handed arm drag broke the grip quite nicely.
If the attacker is about to close in with the lead hand then I will use the Pak Sau due to it's speed and economy of motion and and because I will need the other hand to posssibly deflect the knife .
As I said I am no Judo or grappling guy so your results might vary , but as a Wing Chun guy I am no stranger when it comes to manipulating peoples arms.
This is just what worked for us , the attacker was very enthusiastic and came in hard and stabbed like a Singer sewing machine.