There are essential rules to knife defense. Rules that probably pre-date any known knife defense system – ie. recognize the threat as immediate and life threatening, get out of the way of the on coming attack then control the ability of the attacker to come at you again. But from the first time someone took a sharp weapon and thrust it at another, the defender most likely discovered even the most basic of rules generally play out in a complex manner in a real fight..
Many effective knife defense arts work within a simple paradigm. Divert, seize, control and disarm. Systems in some form or another develop from that series of ideas into full fledged and in some cases highly effective knife fighting arts. But instead of following a strict paradigm of rules Systema develops its concept of knife defense from deep natural structures based in the innate human desire to survive.Trying to impose rules on the nervous system can quickly become a zero sum game in a knife fight. It is better to survive first then apply knowledge to the situation. Trying to apply knowledge to instinctual behavior can work, but trusting and developing your instinctual behavior will lead to much more sophisticated, spontaneous and psychologically confusing (for your opponent) defense.
Unfortunately relying purely on instinct is also a losing proposition. I would relate it to realizing that a car is barreling towards you at high speed. What do you do? If you try and figure out the best technique for avoiding the car then apply it, for all the ways and all the completely random positions you could find yourself in the path of a speeding vehicle (it would be very difficult to train a technique for every eventuality).. If you are still thinking about these things you are already under the wheels. No, you recognize the threat by what ever means, sight, sound, a feeling.. and your body immediately leaps out of the way as instinctual survival takes over. But now you are in the air, you still have to survive the landing. This is where knowledge must kick in to recognize your attitude in space and further protect yourself.
This analogy is more akin to Systema’s approach to knife defense. To go back to the primal urge – recognize the threat as immediate and life threatening, get out of the way of the on coming attack, and control the ability of the attacker to come at you again through various and varying methods.
Each of these stages can be trained to become deeply routed, naturally forming principles that allow a completely spontaneous, highly effective and essentially hidden method of defense.
There are many ways to train for the eventuality of knife defense; develop mobility principles for universal motion, exercise to merge with an attackers motion, study a fundamental psychology of knife defense, practice knife disarming and limb destruction, understand softwork principles, work with a resistive opponents, strike, spar etc. But the core of all of this work is to develop from your instinct first and then apply knowledge.
As Vladimir once said to me after an exhaustive day of knife defense drills ‘All this work! In a real fight you probably only get one chance.’ And there it is, better make it a good one.