as the sport grew in the 1960s and 1970s, each nation devised its own set of rules and regulations. the need for more clearly defined and consistent rules for international competitions led to the formation of an ardf working group by the international amateur radio union (iaru) in the late 1970s. the first ardf event to use the new standardized rules was the 1980 world championship. these rules have been revised and updated over the years, increasing the number of gender and age categories into which competitors are classified, as well as formalizing the start and finish line procedures. while some variations exist, these standardized rules have since been used worldwide for ardf competitions, and the iaru has become the principal international organization promoting the sport. the iaru divides the world into three "regions" for administrative purposes. these regions correspond with the three regions used by the international telecommunications union for its regulatory purposes, but the iaru has also used these regions for sports administration. the first iaru region i (europe, africa, the middle east, and ex-ussr) championship was held in 1993 in chtelnica, slovakia, the first iaru region iii (asia and oceania) championship was held in 1993 in beijing, china, and the first iaru region ii (north and south america) championship was held in 1999 in portland, oregon, usa. in addition to participation in international events, most nations with active ardf organizations hold annual national championships using the iaru rules.