| The simple answer is they are pretty much the same thing.
Now that that is out of the way, let me start getting into the specifics. Tang Soo Do (The Way of the Tang (dynasty in China) Hand) was originally one of the Korean translations for Karate-Do during and just following the Japanese occupation of Korea from 1910-1945. Moo Duk Kwan (institute of martial virtue) was founded by GM Hwang Kee and was just one style (Kwan) of Tang Soo Do (though most looked like a Koreanized version of Japanese Shotokan Karate/Okinawan Shuri-Te Karate, which Tang Soo Do is most known for today).
In 1955, the Kwans met to consolidate their efforts and form a 'new' Korean national martial art, (orginally called Tae Soo Do, later renamed) Tae Kwon Do. GM Hwang Kee's Moo Duk Kwan refused to join up and stayed seperate.
Eventually, Moo Duk Kwan Tang Soo Do made its way around the world, usually just called Tang Soo Do, but often changes crept in. Instructors changed forms to suit them or their understanding of the applications. Some instructors threw them out entirely. Others added 'new' moves, etc. As the changes occurred so too did political disagreements and thus people broke away to form their own federations and organizations. GM Hwang Kee wanted to keep his Moo Duk Kwan as he originally wanted it. He called for all loyal Moo Duk Kwan stylists to join the newly renamed Soo Bahk Do Moo Duk Kwan. He then introduced several new forms, the Chil Sung Hyungs (or Seven Star forms) and Yuk-Ro Hyungs. These were supposedly created from GM Hwang Kee's training in Chinese Kung Fu and his study of the Muyo Dobu Tongji, an old Korean martial manual. (Please note, I am not entirely certain the timely of when the Chil Sung and Yuk Ro were created and introduced, nor the creation of the Soo Bahk Do Moo Duk Kwan Federation due to conflicting sources, but this is in general). Most Tang Soo Do dojangs in America are likely based on earlier Moo Duk Kwan Tang Soo Do, but they either chose not to join up with the SBD MDK federation or they belong to another organization. I hope this helps clear some things up! |