National Route 425
Among Japan’s many mountain roads, few carry the reputation of National Route 425. Known unofficially as the “酷道425” — a pun combining kokudō (national highway) with kokudō meaning “cruel road” — Route 425 has become legendary among adventurous drivers and cyclists alike. Stretching through the remote mountains of the Kii Peninsula, the route connects parts of Mie, Nara, and Wakayama Prefectures, cutting through some of the most isolated terrain in western Japan.
About National Route 425
For cyclists seeking a genuine backcountry challenge, Route 425 offers an experience unlike almost anything else in the country.
The most famous section lies between Totsukawa in Nara Prefecture and Ryujin in Wakayama. On paper it appears to be a national highway, but expectations of wide lanes and smooth flowing traffic quickly disappear. Much of the road narrows to barely a single lane, with crumbling edges, overgrown vegetation, blind corners, and steep drop-offs protected only by aging guardrails — if any exist at all. In some sections, rockfall and landslide damage are constant threats, and temporary closures are common after heavy rain or typhoons.
For cyclists, however, this harshness is exactly what makes Route 425 special.
Traffic is remarkably light. Entire hours may pass without seeing another vehicle, particularly on weekdays. The silence of the surrounding cedar forests becomes one of the defining memories of the ride. Rivers cut through deep valleys far below, while mist often hangs over the mountains in the early morning. Unlike many of Japan’s more famous cycling routes, Route 425 feels truly remote and untamed.
The physical challenge is substantial. Climbs are relentless, gradients frequently spike into double digits, and there are very few opportunities to restock food or water once deep into the mountains. Convenience stores are effectively nonexistent along the core sections, so careful preparation is essential. Riders should carry enough supplies for a full day and ideally have offline navigation, lighting equipment, and basic repair gear. Mobile reception can also be unreliable in several areas.
Weather plays a major role in determining whether the route is enjoyable or dangerous. After rain, moss and fallen debris can make descents treacherous, while summer brings oppressive humidity and swarms of insects. Winter can introduce ice and occasional snow at higher elevations. Spring and autumn are generally the best seasons, particularly during the autumn foliage period when the mountains of the Kii Peninsula turn brilliant shades of red and gold.
Despite its intimidating reputation, Route 425 is not simply a suffering exercise. It represents a side of Japan that many visitors — and even many Japanese cyclists — rarely experience. Tiny hamlets cling to steep hillsides, abandoned buildings slowly disappear back into the forest, and old mountain culture still lingers in the valleys. The road feels less like infrastructure and more like a fragile thread connecting isolated communities.
For experienced cyclists who enjoy difficult mountain riding, National Route 425 is one of Japan’s ultimate adventures. It is demanding, occasionally uncomfortable, and sometimes genuinely intimidating. Yet those very qualities are what make it unforgettable. Riding Route 425 is not about speed or efficiency; it is about immersion in the rugged geography of the Kii Peninsula and experiencing one of the country’s last truly wild national highways.
The Route
Route 425 crosses the Kii peninsula between Owase in Mie Prefecture and Gobo in Wakayama Prefecture. Both ends are on the Pacific Cycling Route
See other’s and share your experience riding this road on Cyclists’ Road Map
Things to do and see
Hatenashi Village
Perched high on the mountainsides of the Kii Peninsula, Hatenashi Village is one of the most atmospheric settlements along the historic Kumano Kodo pilgrimage network. The tiny hamlet is famous for its terraced stone walls, narrow lanes, and traditional homes overlooking the deep valleys of Wakayama Prefecture. Located near the Hatenashi Pass on the Kohechi route, the village has long served as a resting point for pilgrims crossing the rugged mountains between Koyasan and Kumano Hongu Taisha. Despite its remote location, Hatenashi retains a timeless rural character, with carefully maintained rice terraces and sweeping mountain views that showcase the quiet beauty of Japan’s interior. For cyclists and hikers alike, reaching Hatenashi Village feels less like visiting a tourist attraction and more like discovering a living fragment of old Japan.
Places to stay
Despite being a road through the mountains, there are some places to stay, in particular around Totsugawa Village (86km mark) as well as just entering Tanabe City (125km mark) but as there aren’t many, they should be booked in advance
