Self-defense techniques taught in martial arts gyms are so complex and difficult that ordinary people cannot use them as freely as they want in a real fighting situation. So, I introduced easy and powerful self-defense techniques in this book. Due to the danger that they might cause serious injuries or even death if used wrongly, these techniques are not taught at martial arts gyms. And Modern martial arts prohibit the usage of these techniques as they call them foul plays. In dealing with violent crime, sports martial arts have its limits. In my point of view, we need to use all the defense techniques including what modern sports martial arts call 'foul play' in order to protect our self-respect and our family from violence. I'm sure this book will be very helpful when you are in danger.