Duncan trained privately with Yip Man from '55-59 and fully mastered the system and it's applications. He didn't train in the regular school with the other students, Yip Man came to his house. He had to fight in order to learn how to use the techniques and is a veteran of literally hundreds and hundreds of fights. Teaches what he calls "Applied Wing Chun", saying Yip Man taught a lot of people Wing Chun, but taught him how to apply it. For example, Yip Man sent his later disciple Allen Lee to train with Duncan to learn how to use Wing Chun.