Which kwon is the root style of tae kwon do?

Answer 1

Rather than a "style" or structured curriculum like we see in modern Martial Art schools, Taekwondo was developed by merging several influences from ancient Korean grappling and hand fighting of Subak, kicking of Tae Kkyeon, military training and character cultivation of the 7th century Hwarang Knights, and Chinese hand fighting of Tangsudo (aka: Tang Soo Do).

In modern times, the founders of Taekwondo were influenced through the forced occupation of Japan, and their native martial art systems of Shotokan Karate, Judo, and Aikido. These influences contributed a structured teaching method with training aids of forms called "kata" in Japan, and "tul," "hyung' or "poomsae" in Korea, and a belt grading system shared by most modern schools of Martial Art. After WWII, the re-emergence of native Korean methods, inspired primarily by the predominant kicking weapon of Tae Kkyeon (aka: Taekyon).

Soo Bak Do (Developed by Yi Sung Kye) 1392 A.D.

Answer 2

The word you are thinking of is "Kwan" (관 ) which refers to a related group, family, or clan. It is used in Taekwondo to denote a system of teaching under one leader - - the Kwanjang. While the answer to this question could be debated among experts, the first "official" Kwan that was established in 1944, and approved by the occupying Japanese government, was the Chung Do Kwan (청도관), founded by Won-Kuk Lee (Yi, Won-Kuk).

After the end of World War II, the Chung Do Kwan grew to become the largest civilian Kwan, and most of the later annex Kwans were started by Black Belt graduates of the Chung Do Kwan under Grandmaster Won-Kuk Lee (with a few exceptions).

However, when the name of "Taekwondo" was chosen in 1955, it was a group effort to unite the main Kwans, and the formation of the Korea Taekwondo Association (1961) was the beginning of this unification process. Each of the several Kwans contained curricula that varied with influences from Subak (Korean hand strikes and grappling), Hwarang (both concept and warrior's code of the Knights of the Hwarang Youth Group), Tae Kkyeon (Korean kicking), Tangsudo (aka: Tang Soo Do / Way of Chinese hand), Shotokan Karate-do, Aikido/Hapkido, and Judo/Yudo.

All of these influences, and each of the Kwan founders, as well as their lead Black Belts were responsible for contributing to the development of the modern Korean Martial Art that was to become known as Taekwondo, and selected as the National Martial Art of Korea.