Shiratani Unsuikyo is a ravine gorge in the northwest of Yakushima, easier to reach and less physically demanding than the Jōmon Sugi trail. A network of wooden boardwalks and paths winds through ancient cedar groves where the rocks, roots, and forest floor are buried under thick, luminescent green moss. The light filters through the canopy in shifting dappled shafts, and streams rush over boulders below.
There are several trail loops of varying difficulty within the ravine, ranging from a one-hour stroll along the lower boardwalks to a half-day circuit up to Taikoiwa — a viewpoint on a bare granite rock with views across the forested hills. The trails are well-marked and the access road is open to private cars, making this the most accessible of Yakushima's major forest experiences. Go on a weekday if you can; the ravine draws large crowds on weekends, which rather breaks the spell.