For self-cultivation

My nephew is interested in martial arts and he just enrolled in the training. He asked me more information about it but I don’t have any idea. What I know martial arts is use to defeat a person physically or to defend oneself from physical threat. He explained to me, it is also consider as practices and traditions of training for combat. Martial arts develop a combat skills, fitness, self-defense, sport, self-cultivation/meditation, mental discipline, character development and building self-confidence. I was fascinated learning about it and motivated to learn also martial arts. I admire those people who already perform this kind of great combat skills.