PRIME ingredient in the remarkable economic growth and stability of Japan during the past decade has been the dramatic increase in the supply of electric power for residential, industrial, and commercial use.' Between 1952 and 1963 energy sales by electric utilities had an average annual increase of more than 12 percent. Both installed capacity and output of electric energy roughly tripled, the former to 29,142,000 kw and the latter to 136,758 million kwh.2 Japan has moved to fifth rank in the world in installed capacity, behind the United States, the Soviet Union, the United Kingdom, and West Germany. In electric-energy output, however, it has passed West Germany and is challenging Great Britain. Behind this advance are striking changes and improvements in Japanese electric-power technology, territorial organization, and coordination of power production.