Nikobuchi, which is located upstream of the Niyodo River, is one of the best spots in Japan, and is said to be "this blue is Niyodo blue." It is a small deep pool where the clear stream flows straight down, and it is so clear that you can see the bottom even though it is the base of the waterfall. The basin at the bottom of the valley surrounded by trees receives a faint amount of light, and the color of the water changes from green to blue depending on the time of day. By the way, the best time to see "Niyodo Blue" is around noon when the sun shines down from directly above, and many tourists visit during this time.