Kicking style of Martial Arts, developed by the need for unarmed infantry to strike up toward mounted house soldiers in feudal Korea. No more of a sport, and as such has adapted to become more 'sporting' with rules and editing techniques (for example, kicking was traditionally done with the ball of the foot, being a hard surface to do more damage, but now it is preferred to use the instep so the judges can hear the slap from contact better).
Relationship to Krav Maga
Other than the fact that they are both striking styles... there is no relationship.