In the mid 1980s, a top Swedish orienteer developed an alternative to the baseplate compass by reshaping the baseplate and adding a strap for attaching the compass to his thumb. This compass is then placed on the thumb of the left hand, which holds it on the map. The advantage of this system is that the map and compass are always read as a unit, the map is aligned more easily and quickly, plus one hand is left free; the disadvantage is that running very accurately on a bearing is more difficult. Pe rsonal preference usually determines the type of compass that is used; world championships have been won using both types.