In hoplology, attack and defense are definitely considered distinct. Moreover, hoplology separates “defend” and “protect.” While in the common vernacular “defend” and “protect” are often used interchangeably, for hoplological purposes, while “protecting” and “defending” are somewhat related, they are two distinct concepts.
Hoplologically, “to defend” is basically a single minded effort to keep one’s whole self (or group) from being harmed or damaged by an attacker. This might include fighting back, but not necessarily so. The concept of “whole self” is key in this. One generally does not defend one’s arm or leg or partial body area. Hoplologically, this general concept applies on a military level as well. “Defense,” in the tactical and strategic sense, implies the lowering of the enemy’s ability to mount an effective attack. In either case, an important aspect of “defense” is the mindset behind defending. Actively defending against an assault tends to be a single minded intent to keep from being harmed. Going on the attack in such a situation is typically a separate and often a secondary action. In a life-death or battlefield combat context, this can be mortally inefficient. The classical attempts to remedy this defense/offense dichotomy is by such notions as “the best defense is a good offense” or kobo itchi – (攻防一致 “attack and defense are one”).
Hoplologically, “protect” is less an end goal than is “defend.” And it is more useful as a means to an offensive end. In personal combat, a shield, for example, is used for protecting parts of the body while in the midst of offensive action. And, as has been pointed out previously in regards to our combative training, “blocking” actions are done protectively but primarily as means to create openings or paths to the target. In particular, such blocking, while typically protective of a particular body part, must be offensive in intent.
Certainly a “protective” action can be used in defense, but it is its use in “defense” that the founder of one classical Japanese battlefield tradition was referring to when he stated, “the blocking mind is useless, a dead thing and weak.”