Oyasukyo Gorge cuts about 60 metres down through the Minase River valley, with a short walking route that brings you close to the steam vents and boiling water known as Daifunto. From the bridge above, the gorge looks tidy and scenic; down near the river it feels more alive, with heat, sulfur, spray, and sound coming out of the rock.
Autumn colour is the famous season, but the gorge is worth seeing whenever the promenade is open. It normally closes through the snowy months, so check current access before making the trip in early spring or late autumn.