Do-San is the pseudonym of Ahn Chang Ho (1878-1938), a famous leader, educator, moral and one of the key philosophical leaders in 20th Century Korea. He called for the moral and spiritual renewal of the Korean people through education as one of the important components in their struggle for independence and building a democratic society. Ahn also included economic and military components in his independence movement strategies. The form was made sometime between 1960-65 as it was not present in Choi Hong Hi’s 1959 book and first appears in his 1965 book. It was from 1965 onward the third pattern taught in the Ch’ang Hon series of forms (Ch’ang Hon being Choi Hong Hi’s pseudonym). If you know the older Karate Kata called Heian/Pinan/Pyungahn you’ll see that there are sequences of the form that is taken from the older forms and reincorporated into this newer form. I really like it :-) I use the 1965 description as a template so the front kicks are delivered to the mid section as that is specifically said to be the target. Likewise I keep my hands in the wedge block position as I kick instead of following the kukki taekwondo Poomsae “rule” to withdraw the arms to guard while kicking, as this is specifically written in the instructions.