In an effort to 'Koreanize' Taekwondo and evolve it from its Japanese Karate origins, in the early 1960's some master emphasized the sport aspects of Taekwondo by developing a system of interrelated kicking techniques, intricate footwork, and attacks/counterattacks that were different from Karate. Emphasis was shifted from form/pattern practice to that of contact sparring.
These major differences allowed sport Taekwondo to develop its unique kicking system, using such things as instep kicks that distinguished it from Karate. Although some these early masters vehemently opposed the changes, the changes were implemented in 1963 with Taekwondo's inclusion in the Korean National Sports Festival.
Another radical difference between sport Taekwondo and traditional Karate based Taekwondo was the change from the traditional attack-block-counterattack method of sparring to that of the attack-counterattack method. The concept of blocking before counterattacking is inherent in traditional Taekwondo and is emphasized in its patterns. As sport Taekwondo evolved through constant experimentation during competition, the block disappeared due to its ineffectiveness in the new system of sparring. Competitors found that, by synchronizing attacks and using intricate footwork, it was possible to kick at the same time as the attacker and counter the attack almost simultaneously without blocking.