For self defense it all depends upon the attack you have to defend against. Normally you are only meant to counter and block an attack, you should not inflict pain on your opponent. However, if your attacker is using a weapon then you can use a more aggressive defensive move to stop the attack and prevent any further attacks. Always remember to block a knife attack with the outer forearm as opposed to the inner forearm as damages to your wrist and hand can be more severe if you are hit on the inner side of your arm. All in all the best defense is to predict the attack beforehand and if possible avoid it rather than going into trouble. (if all else fails you can use your training to outrun the opponent) - just kidding. best regards Boualem Bouderba