Tang Soo Do (Hangul: 당수도, Hanja: 唐手道 pronounced [taŋ.su.do]) refers to a Korean martial art based on Karate and may include fighting principles from subak (as described in the Kwon Bup Chong Do), as well as northern Chinese martial arts.[1] Before the Nine Kwans united and formed the martial art Taekwondo, Tang Soo Do was used by select Kwans to identify their Karate-derived martial arts style.

In contemporary context, after Taekwondo was founded, many Korean martial arts entities continued to use Tang Soo Do as means to preserve the elements of Korean martial arts that evolved from the original nine kwans' Karate roots and were lost in transition to Taekwondo. The techniques of what is commonly known as Tang Soo Do combine elements of Shōtōkan, Subak, Taekkyon, and Kung Fu