Chikurin-no Komichi (around 200m long) runs between Kaede Bridge and Katsura Bridge along the eponymous river. Once you've passed the first bridge, you will see a very famous little pavilion in the middle of the water. It houses the hot spring of Tokko-no-yu (41°C) which, according to legend, gushed forth when Kobo Daishi struck the rock with a tokko (a sort of tantric ritual stick). The monk is said to have been moved by the sight of a child washing his sick father's back with water that was far too cold.