Welcome to the San Francisco branch of the Cardboard Tube Fighting League (CTFL). The CTFL was created out of a desperate need to better train and arm citizens with cardboard tubes. While many speculate that our fore fathers, when drafting the constitution, originally intended the second amendment to refer to fire arms, there is now a small group of non-academics who believe that they were more likely referring to elite militias of card board tube wielding ninjas. While this training often takes place during childhood, it is discarded by adults who remain uneducated about the importance of such practices. The goal of the CTFL is to provide organized cardboard tube based events that help spread cardboard awareness. Among these pages you will find information, history, and event listings for duels in the San Francisco area.