The most demanding hike on the island: a two-day traverse from the Urauchi River across the central mountains to Funauki on the west coast. The trail is rough, often muddy, and crosses several streams. There are no shelters and no facilities — most hikers carry a tent, although day-long shortcuts are possible.
A licensed local guide is strongly advised (and is mandatory beyond certain checkpoints). For experienced trekkers it is one of the best wilderness walks in Japan; for everyone else, a half-day on the Mariudo trail will give a similar flavour with much less risk.