Did some good knife work last night...basic 5 angles cutting and block/parry combos.
Getting attacked with a knife by someone who knows how to use it is a scary situation.
Some key take-aways:
1) Keep your hands tight to your body
Don't let your arms wave around. It just makes it more likely that you will get cut or be out of place. Keep your arms close to your upper body forearms facing outward (protecting vital organs there) when not active.
2) Think SMALL
Keep all actions minimal. Fear will make your motions exaggerated. Success depends on precision.
3) Protect the Big Stuff; use the Outside
Blocking should be done with the outside of the arms, NEVER the inside of the arms.
The inside is where all the key arteries are, and this needs to stay protected. If you are cut on the outside of the arm it is less likely to result in a lethal wound.
4) Focus on the MAN, not the knife
There is a tendency to develop tunnel vision and stare at the knife - staring at it won't make it go away. Knife or not, the attacker is the target. Keep your attention trained on the shoulders so you can see attacking motion develop.
5) Watch your Lines
Make sure you move your whole body, not just your arms/upper body, out of the way of the knife. Stand in one place; die in one place.
6) Finish Up
Like every Kali situation, if you need to use it, you need to use it properly.
Finish your oppenent completely. A knife situation is potentially lethal.
No time to be nice or merciful. There are many cases of fatally wounded attackers still managing to kill their victim before they go out. Make sure the attacker GOES DOWN and STAYS DOWN.
7) Sink the Blade; Sink the Man
When you have the knife...many classic texts on knife fighting emphasize that while slashing/cutting can kill; stabbing is a a far higher percentage stop. The goal is to get a torso stab. In either case, putting the attacker on the ground (via takedown/sweep) is important since it greatly reduces the chance that the attacker will recover.
8) Practice Practice Practice
Train these responses a lot. They will help your empty hand work too.
This is the real deal. Focus. Make sure you are the one that walks away.
In the UK this is becoming a more serious issue: http://edition.cnn.com/video/#/video/world/2008/07/12/simmons.uk.knife.crime.itn
Just because they don't allow guns doesn't make it safe.