Takinohai, Natural waterfall in Kozagawa, Japan

Takinohai is a waterfall on the Koza River in Kozagawa, Japan, where water drops over several rocky steps into natural pools below. The riverbed is made of dark stone shaped by the current, and at low water it is easy to walk close to the base.

The waterfall appears as "Hai no Taki" in the Chōutsuo village entry of the Kii Zoku Fudoki, a topography compiled by Kii Domain in the late Edo period. The riverbed of the Koza River tributary exposes the Kumano Group's Shimosato Formation for about one kilometer, and the falls drop roughly 8 meters. In 2010 the prefecture designated the site a Place of Scenic Beauty and Natural Monument.

In summer sweetfish gather in the plunge pool, and anglers catch them by snagging with a hook rather than bait or fly. The method is called tonton-tsuri because the weight taps the pool floor. Only cooperative members may fish here, as the rocks are uneven and dangerous. Since 1999 the season above Takinohai Bridge has opened half a month later so ayu can climb past the falls.

The waterfall is easiest to visit in the drier months when the water level is lower and the rocky bed is more visible. A small roadside center nearby offers local products and information about the area.

The rock at the base of the falls is dotted with circular holes formed by stones that spun in the current for a long time, slowly grinding into the riverbed. These potholes are rarely this visible and give a clear sense of how the river has been shaping the stone over many years.