The name "Osen" means "an old hermit woman," and one theory states that the waterfall first appeared more than 500-600 thousand years ago. It features a 25-meter drop, its waters flowing down delicately, emiting quite a feminine atmosphere. There is a promenade that can take visitors down to the waterfall, but one needs to exercise caution when descending, for there is a steep slope with a stretch of a rope along the way. A huge Katsura tree stands at the side of the falls, and with a height of 35 meters and trunk circumference of 6.7 meters, it has been chosen as one of the "100 Best Forest Giants" and is a must-see.