Steep gradient, downcutting stream. The Sacred Bridge at Toshogu Shrine, Nikko. -- As rivers downcut and reduce their gradient, they tend to eliminate rapids and waterfalls. Because of more-or-less constant uplift in Japan, rivers typically have not been able to accomplish this. This river has rapids and falls indicating a steep gradient. There are no flat surfaces adjacent to the stream to indicate that it is shifting laterally. This is a small, fast-flowing, actively downcutting, short river typical of most of the rivers of Japan.