When executing Soto Uke, what is the critical biomechanical purpose of the circular outward motion, beyond simply deflecting the attack?

Beyond simply deflecting an incoming attack, the circular outward motion of Soto Uke serves the critical biomechanical purpose of redirecting the opponent's force away from the defender's center line while simultaneously setting up a potential counter-attack. The circular motion uses the defender's entire arm and body to change the angle of the attack. If a straight block is used, energy is absorbed. By changing the angle, the block redirects an attacker's force to make the attacker unbalanced, or creating an opening. The outward motion is not just about moving the attack away; it's about controlling the attack trajectory to create an advantageous position. Furthermore, this circular movement helps to generate momentum and power for a subsequent counter-attack. The momentum created during the circular motion of the block can be immediately channeled into a strike or grab, increasing the speed and force of the counter. This combines defense and offense into a single fluid movement, making Soto Uke a versatile and effective technique. For example, after deflecting a punch with Soto Uke, the practitioner can seamlessly transition into a punch or elbow strike, using the momentum from the block to enhance the power of the counter.