Koshi Waza refers to a category of techniques in Judo that primarily involve using the hips to throw an opponent. These techniques leverage the strength and movement of the hips to create balance disruption, allowing a judoka to execute throws effectively. Koshi Waza is essential for developing a strong foundation in Judo, as it emphasizes body mechanics and leverage. Common examples of Koshi Waza include O Goshi and Uki Goshi, which are fundamental hip throws. Practicing these techniques helps judokas improve their overall skill set, enabling them to apply hip movements in various situations during a match.