Many, many moons ago there was a fair king who oversaw 10 villages. As the king, he required a village tax of 1 gold bar per day per village. Each gold bar is supposed to weigh 1000g and have the village name etched in to it. However, the king has learned through an informant that one village has been cheating him the whole time and only giving him a bar that weighs 999g.
The king is furious and orders a scale to be brought in to test the weight of the gold bars. Assuming the king has access to all the gold bars ever sent to him, how can he figure out which village has been cheating him the whole time by using the scale only once?