Tang Soo Do (Korean: 당수도; Hanja: 唐手道; pronounced [taŋ.su.do]) is a Korean martial art based on karate which can include fighting principles from taekkyeon, subak, as well as northern Chinese martial arts. From its beginnings in 1944 to today, Tang Soo Do is used by some Kwans to identify the traditional Korean fusion of fighting styles. In the mid 1950s, it became the basis for the martial art taekwondo when the Korean Nine Kwans united.
In contemporary context, many Korean martial arts entities continued to use Tang Soo Do 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.