In my experience of Ninjitsu, it is the eyes, the groin,the sternum and just abbove the point where the collar bones join

St 5 is my all time favorite. I keep finding more ways and contexts to attack it.

Those are good vital points TwinDragonsNinja. We study ABOUT them, but we don't generally practice hitting them. We DO practice above where the collar bones join, but not the eyes or groin. Some people practice sternum. I consider it unsafe and I do not, at least not for striking applications. I use it for touch and rub only. Too dangerous for my liking in practice. If I were fighting for my life for real, I'll look for the eyes.

Last month, I accidentally got a corneal ULCER in sparring bare handed practice. I've had corneal abrasions before but this was my first ulcer. The eye was blind and painful for 2 days and full vision not returning for a month. I was seeing double edges around lights and while reading.

When you get this kind of eye injury, the pain is severe and it is very hard to fight. Additionally, what you can't control, even if you can fight through the pain, is the tearing. it is hard to see through that much tearing. In my case, I could not open the eye until I got to the emergency room and the doctor numbed it. I had to close the other eye too to stop my eyes from moving around. If one eye moves, the effected eye moves too and that movement hurts. I just hit the floor so that it would be obvious that I was in trouble and uke would stop.

I am very much aware that a deliberate eye strike would have been much more severe. I'd say that probably no strike is so effectively and totally disabling as the eye strike.

I now wear goggles for sparring.