Do San is the third pattern learnt for the ITF style of Tae Kwon Do, and it is therefore, along with all previous patterns, required for the fourth grading, promotion from green tags (7th kup) to green belt (6th kup).
The definition of the pattern is as follows: "Do San is the pseudonym of the patriot Ahn Chang Ho (1876-1938). The 24 movements represent his entire life, which he devoted to furthering the education of Korea and its independence movement."
This is the first pattern to include foot techniques (kicks), and the use 45 degree angles in addition to the usual compass points. Many students find this pattern confusing to learn, due to similarities to the previous pattern, Dan Gun. The movements for the pattern, and its diagram, may be found at http://www.itf-information.com/sub0403.htm.