Shiratani Unsuikyo Ravine Entrance
The Shiratani Unsuikyo Ravine is Yakushima’s best-known and most-frequented destination. The valley’s terrain of dense woodlands and plunging waterfalls covers 424 hectares and ranges in elevation from 600 to 1,050 meters. Three trails of varying lengths take hikers across pristine streams, through old-growth conifer and broadleaf forests, past thousand-year-old Japanese cedar trees (yakusugi), and into the otherworldly Moss-Covered Forest.
From Tsujitoge Pass, connecting trails lead on to the Arakawa Trail, the Okabu-hodo Mountain Trail Entrance, and from there to Wilson’s Stump (5.7 km from the Pass, approximately 2 hours and 40 minutes), the Jomonsugi Cedar (7.6 km from the Pass, approximately 4 hours and 10 minutes), and eventually Mt. Miyanoura (1,936 m), the highest peak in Kyushu Prefecture.
Sights along the Trails
Yayoisugi Cedar Loop Trail: This is the ravine’s shortest route, which is 2 kilometers long and takes approximately 1 hour. The highlight is the Yayoisugi Cedar, which is estimated to be 3,000 years old and is named for the Yayoi period (300 BCE–300 CE). This giant was never cut for timber as its complex shape would have made cutting straight planks difficult. Today, the tree stands 26.1 meters tall and has a trunk circumference of 8.1 meters. The Yayoisugi Cedar’s easy accessibility has made it one of the most-visited yakusugi on the island. It stands in a grove of flowering isunoki, a type of witch hazel.
Bugyosugi Cedar Loop Trail: The greatest number of yakusugi are found along this middle-length trail, which is 4 kilometers long and takes approximately 3 hours. The seven major yakusugi along this course include the Nidaiosugi Cedar, or “second-generation great cedar.” At 32 meters high, this tree is both the valley’s tallest and an example of “stump regeneration,” in which a tree sends out new shoots from an old stump. The trail also leads past the “three-legged” Sanbon-ashi-sugi Cedar and the Bugyosugi Cedar, which has the largest trunk circumference in the ravine at 8.5 meters. Visitors may notice a scar on its trunk, which is the result of a “test cut” made several hundred years ago by loggers. They were testing whether the wood would split evenly, but ultimately deemed the tree unusable. The final yakusugi giant visible along the Bugyosugi Cedar Loop Trail is the Kugurisugi Cedar, whose roots arch over the trail at the point where it turns back toward the ravine entrance.
Taikoiwa Rock Loop Trail: This is the longest and most popular route in the ravine. It covers 5.6 kilometers and takes approximately 4 hours. Its main attractions are the Moss-Covered Forest (Kokemusu-mori) and Taikoiwa Rock (1,050 m), the highest point on the three trails. First, hikers will reach the Moss-Covered Forest—a spectacular, boulder-strewn landscape where the constant high humidity and minimal leaf fall encourage the luxuriant growth of moss on every surface. Roughly 1.2 kilometers past the forest, hikers will reach Taikoiwa Rock. This large granite outcrop offers an expansive view of the Anbo River and Yakushima’s interior mountains, including Mt. Miyanoura and Mt. Nagata (1,886 m). From the Rock, visitors can see Kosugidani Valley, the location of a former logging village.
In spring and summer, Shiratani Unsuikyo Ravine is filled with flowers: pale pink azaleas in April, sapphireberry and Japanese rowan blooms from April to May, white hydrangeas from May to June, scarlet azaleas in early summer, and the camellia-like blooms of orangebark stewartia in August.
Continuing On
The Okabu-hodo Mountain Trail leads first to Wilson’s Stump, the remains of a massive Japanese cedar tree that was cut down in the sixteenth century. It is believed to be the oldest stump on Yakushima. Roughly 1.1 kilometers later, hikers will reach the Daiosugi Cedar, estimated to be around 3,000 years old. Another 0.8 km along the trail is the Jomonsugi Cedar, said to be the island’s oldest and largest Japanese cedar. The Okabu-hodo Mountain Trail rises steeply from this point, and 5.6 kilometers after the Jomonsugi Cedar, hikers will reach Mt. Miyanoura.
Cautions
Much of the route from Tsujitoge Pass to the Jomonsugi Cedar is very steep, and hikers taking this route should plan on two full days. Those headed to Mt. Miyanoura will also need to stay overnight in a shelter. This route may be especially dangerous in snowy winter conditions.
The Bugyosugi Cedar Loop Trail crosses several creeks, which swell during and after rainfall; be careful of rising water and slippery rocks. The trail may be closed if conditions are unsafe. Check for a sign posted at the Shiratani Unsuikyo Ravine Entrance or ask park staff about route closures before beginning a hike.
Yakushima macaque monkeys and Yakushima shika deer, as well as many different types of amphibians, insects, and birds inhabit this area. For the protection of plants and wildlife within the national park, visitors should remain on the trail at all times and refrain from feeding animals, polluting water sources, stepping on live moss, or leaving any trash behind. Camping in unauthorized areas, starting fires in the forest, and catching or harming living things are all prohibited by law.
Weather conditions on the island can change quickly. Watch for falling branches or rocks along the trails. Cellular phone service is largely unavailable, but some areas do get signal, so hikers should carry a phone in case of emergency.
There is an outhouse as well as a booth for disposable-toilet use near Shiratani Hut along the Taikoiwa Rock Loop Trail. There is another disposable-toilet booth at Tsujitoge Pass. Hikers are advised to carry a disposable-toilet pack for emergencies and to use the facilities here at the trail entrance before entering the forest.
