Jōmon Sugi is the most famous of all the yakusugi cedars — old-growth Cryptomeria trees that grow in Yakushima's high interior forests. It sits at around 1,300 metres elevation, reachable only on foot via a trail that takes most walkers five to six hours each way. The name comes from the Jōmon period, Japan's prehistoric era, because the tree may be older than recorded Japanese civilisation.
The trail starts at Arakawa trailhead, reached by shuttle bus from Yakusugi Land car park (private cars are not permitted). The first two hours follow a former forestry railway line on flat boardwalk — easy walking through a tunnel of forest. Beyond the railway section, the trail climbs through increasingly impressive ancient cedar groves before arriving at a viewing platform a few metres from the tree. You cannot touch it; a metal fence keeps visitors back. But the scale is arresting — the deeply furrowed trunk rises far above you before the crown opens out. Give yourself a full day and start early; the last bus back leaves in the late afternoon.