Genbikei is a two-kilometre ravine carved by the Iwai River through volcanic rock near the city of Ichinoseki, in the southern part of Iwate. The name means "stern beauty" and the description fits: the gorge walls are sheer dark basalt, the water drops through a series of pools and cascades, and the narrow path along the rim gives constantly shifting views.
The gorge is not dramatic in the manner of a waterfall park, but it rewards an unhurried walk. The rock formations have been shaped by water into hollows, arches, and ledges. The gorge is most striking in autumn when the trees above the walls turn, and the coloured leaves against the dark rock and white water make for excellent photography. The walk along the maintained path from one end to the other takes about 45 minutes. Ichinoseki Station is the access point, with the gorge about four kilometres from the town centre — a taxi or bicycle is the easiest way out.