In order to justify their existence and to attract students, many (if not most) martial arts schools make claims about their usefulness in "self-defense". Such claims are a matter of constant debate among beginning level students of the martial arts.
Self-defense situations happen with extreme rarity in most modern societies where such martial arts classes exist, and what situations do develop can generally be avoided by other means (e.g., not walking around drunk in bad neighbourhoods, not buying or selling
illegal drugs, not getting involved with
biker gangs, and so on). Therefore understanding what is needed for self-defense requires understanding the situations that are likely to arise.
There has been an ever-increasing perception among the general population, fuelled by the mass-media, that they are in constant danger of violence on the streets. It is this fear that self-defense classes are intended to counter. Since the fear is largely unfounded, self-defense classes need only reduce the feeling of fear in order to be effective. In practice, for the people to whom these martial arts classes are being marketed, the most likely situation in which they will experience a physical confrontation is
domestic violence.
Finally, the largest problem confronted by most people who are attacked is not a lack of physical ability to resist but an emotional reaction: a paralyzing panic or an undisciplined, blinding rage will turn a bad situation into a potentially disastrous one.
All this said, years of serious training in martial arts are expected to take the emotional charge out of physically violent confrontations (after hundreds of hours of sparring, a punch or a kick becomes just a fist or a foot, a purely physical force, reduced by experience to something easily dealt with and not a "personal" attack as such) and gives practitioners good general coordination and confidence, both of which can discourage aggressors before aggression begins. So, the experience of physical interaction over an extended period of time in martial arts training may be more relevant to its overall effectiveness at practical self-defense than any individual technique the art in question may include.
The self-defense aspect has also changed the techniques used. In our modern world, we may be attacked by an unarmed person, someone with some sort of clubbing weapon (a baseball bat) or armed with a knife. The chance of being attacked by a fully armored, sword-wielding samurai is practically zero. Most martial arts included battlefield combat techniques in the past, but the emphasis on such techniques has declined in most styles.
