Patterns are various fundamental movements, most of which represent either attack or defence techniques against imaginary opponents set to a fixed and logical sequence.
The first Korean school (Chung Do Kwan) was founded in 1944; the original forms practiced in this and the Oh Do Kwan founded by General Choi were the Pyong-Ahn forms, taken from the Pinan / Heian kata of Shotokan Karate, the style learned by the founders of those schools.
The first specific Taekwon-Do pattern, Hwa-Rang, was created in 1956 followed by a further 23 pattterns between 1956 and 1972 to complete the set of 24. Initially these were known as hyung, later renamed to tul, and collectively known as the Ch’ang-Hon pattern set. In 1983 the pattern Ko-Dang was replaced by Juche to finalise the set practiced to this day by ITF stylists.
Following the split in Taekwon-Do and the creation of the WTF in 1973 a new pattern set (poomsae) was developed for their use, called Palgwe. These were later changed to the Taeguk patterns.