I don't know any statistical numbers, but they tell me that the majority of duels in japan were won by stabbing into the chest.
Kinda takes all the piss out of the legendary cutting ability of the Japanese sword, doesnt it?
The katana does cut well, but when it came time to live or die, they did whatever they had to do and it seems the thrust to the solar plexus was a very popular method.
I guess the point I would like to make is that the idea of a backslash is a part of fencing. One may very well be killed by it, but a warrior would avoid such a situation where he could be killed by a fencer. Duelling is a game where one CHOOSES to stand in proximity to someone who wants to kill you under certain limited circumstances.
That is not combat and it is not the way of the warrior.
Having said that, any good warrior will learn about the backslash and how to defend against it.
Just dont let your focus get so narrowed as to look at the hand manipulations of a fencer in a duel. Try not to get focused beyond the movements of the body of a warrior as he does what is necessary to survive.
From the very instant someone tries to hurt you, you should be moving back and offline, out of the range of his attack. As soon as he has overextended himself, feel free to hack off any offending body parts with your 22" ganga ram.
If you are at least 1mm out of range, as you should be, it wont matter if he has a knife with 18 million edges and can cut in all directions at once like Shiva.
It also wont matter if your knife is 2" long and single edged, once he is overextended and off balance, you can take him down safely and without effort.