This article examines the importance of effective marking in Ultimate Frisbee. It explains that good marking requires both physical and mental skill, as well as the ability to read the offense and respond accordingly. The article dives into the fundamentals of marking, such as good positioning, footwork, and decision making. It outlines a few key concepts to consider, including remaining in between the disc and the receiver, using a variety of active defenses, and focusing on the hips of the offensive player. Ultimately, the article emphasizes the importance of effective marking for team success on the field.