Like many aspects of Taekwondo, the use of patterns was influence by Karate, which began in Okinawa. In the early 1900's, Karate pattern instruction in Okinawa underwent a metamorphous. In 1901, Master Yasutsune Itsou taught Karate as a part of the physical education program at the Shuri Jinjo elementary school. He thought Karate was too dangerous to be taught to children so he taught patterns that were mostly blocking and punching techniques and disguised the dangerous aspects of the patterns. The children gained improved health and discipline from their pattern practice without recognizing the dangerous fighting techniques contained in the patterns. When teaching the patterns to adults, Itsou would give full instruction in all the deadly techniques in the patterns. Thus patterns may be performed either for better health or for increasing fighting skills. The patterns were the same, the difference was in the way they were taught.
Another reason techniques in patterns of today are not taught as they were originally conceived is because of the changes patterns underwent when Karate was introduced into Japan. To be accepted by the Japanese, Karate had to adapt to the Japanese way of training. Because of Judo's influence, there Karate had to adopt a standard training uniform (a lightweight Judo gi was adopted). A method of competition and a standardized ranking system had to be devised. Again the Judo way of doing things was adopted and adapted. The Japanese felt Karate was too violent so the eye gouging, throat crushing, testicle seizing, and other such techniques were hidden away within the patterns and no longer taught openly.
The changes that patterns underwent did not diminish the effectiveness of their techniques, but the changes did create misunderstanding about patterns. Today, most students simply practice patterns to gain rank or win trophies, and thus are only concerned with a pattern's appearance. They tend to forget, or never learn, that the purpose of patterns is to teach how to block an attack and inflict pain upon the attacker. Some think that the performance of a perfect pattern is more important than any meaning that may be gained from it. Gichin Funakoshi, in his book Karate-Do Kyohan states, "Once a form has been learned, it must be practiced repeatedly until it can be applied in an emergency, for knowledge of just the sequence of a form in Karate is useless."