What is the fundamental difference between the application of Shuto Uchi versus Tettsui Uchi in terms of target area and intended effect?

The fundamental difference between the application of Shuto Uchi and Tettsui Uchi lies in their target areas and intended effects: Shuto Uchi targets vital points like the neck or collarbone to cause sharp pain and disrupt the opponent's structure, while Tettsui Uchi targets broader areas like the head or ribs to cause blunt force trauma and disorientation. Shuto Uchi, or knife-hand strike, utilizes the edge of the hand to deliver a precise and focused blow. The intended effect is typically to cause intense pain, disrupt the opponent's balance, or damage delicate structures. Common target areas include the side of the neck (carotid artery), the collarbone, or the base of the skull. This is used to stun or cause harm. Tettsui Uchi, or hammer-fist strike, utilizes the bottom of the fist to deliver a more forceful and concussive blow. The target areas are generally larger and more robust, such as the side of the head (temple), the ribs, or the upper back. The intended effect is to cause blunt force trauma, disrupt the opponent's equilibrium, or inflict temporary incapacitation. To compare, Shuto Uchi is similar to a precise knife cut while Tettsui Uchi is similar to a hammer blow. Shuto Uchi requires greater precision, and Tettsui Uchi requires more brute force.