To the best of my knowledge Tang Soo Do is based on Tae Kwon Do which it evolved from. A Tae Kwon Do instructor started calling his particular version of the art Tang Soo Do and the name stuck and is used for the art of his lineage to this day.Another thing to consider if you have a background in Shotokan is Korean Tang Soo Do, which, despite the protestations of some, seems to be based on Shotokan, and practices similar, and in many cases the same forms.