What Is Belomancy?
One method would involve tying different answers to a question to different arrows and then firing them. The answer was taken from the arrow that flew the farthest.
Another method would simply involve shuffling the arrows in a container, like a quiver, and selecting one — a bit like picking straws.
It is unclear whether those performing the belomancy were treating it simply as a method of generating a random answer or as a method of attaining an answer through divine intervention. If the latter, mumbo-jumbo-meter: 9/10.