A fast, arcing kick delivered by rotating the hips and snapping the knee so the lower leg whips across the target. From guard, pivot the support foot ~70–90° to open the hips, lift the knee across the centerline (tight chamber), then extend sharply. Strike with the instep for reach/speed (sport TKD), the ball of the foot for penetration, or the shin only if your ruleset allows. Re-chamber immediately and recover guard; land back or step through depending on distance.