In ancient times, rice malt syrup was believed to be of divine origin. As if by some heavenly plan, the addition of a few sprouts of barley to rice resulted in golden liquid sweetness. Rice was considered a gift of the gods, and its transformation into an ambrosial liquid sweetness was only allowed to take place in shrines and sacred places.
In modern Japan, traditional rice malt syrup, called mizu ame ("sweet water"), is hard to find. In fact, you may be more likely to find authentic rice malt syrup in an American or European natural foods store than in a modern Japanese supermarket.