OSAKA, Japan — A thin layer of moss coated Buddha’s face with green, and time had worn his little head into a featureless globe.

“How old is this little shrine?” I asked Tetsuo Nakahara, my guide through the dense forests of the Kii Peninsula.

“Same as the others,” Tetsuo answered, barely slowing his pace as we hiked past the small religious monument. “Probably 500 years.”

The sheer age of Japan’s rural monuments is breathtaking. Yet this 500-year-old Buddha ranks as a mere adolescent compared with the Kumano Kodo itself, a religious pilgrimage route akin to Spain’s Way of St. James. The Kumano Kodo traverses the Kii Peninsula, a triangular landmass some 50 miles south of Osaka, and has led the faithful through Japan’s hinterland for more than 1,000 years.

Over rocky mountain pathways slick with moss and across ice-cold streams, beneath thick cypress forests and through humble villages, Kumano’s trail network fans out, linking three important Shinto shrines: Kumano Hongu Taisha, Kumano Hayatama Taisha and Kumano Nachi Taisha. Taken together, they’re known as the Kumano Sanzan.

The Kumano trails also connect countless subsidiary shrines, places of worship and rest called oji, from trailside Buddhas to tiny Shinto sanctuaries. Centuries ago they snaked northward to the ancient capital cities of Nara and Kyoto.

Since 1992, Walk Japan has introduced a pedestrian’s-eye view of Japan’s back roads to English-speaking travelers. Guiding small groups of no more than 12, the tour company explains Japanese history and sheds light on local culture. Practical necessities are taken care of, too, including prearranging travelers’ accommodations, organizing meals and transporting hikers’ luggage from inn to inn.

Walk Japan offers guided treks along such historic routes as the Nakasendo Way, an ancient highway running between Kyoto and Tokyo, and the Narrow Road to the North, made famous by 17th-century Japanese poet Basho. But among the company’s most popular tours is the Kumano Kodo, the ancient Shinto and Buddhist pilgrimage route.

The Japanese Emperor Uda is believed to have been the first to blaze the Kumano Kodo in the year 907. Drawn to a land considered sacred by both Shinto and Buddhist practitioners, Emperor Uda set out in search of seclusion, physical exertion, spiritual enlightenment and the promise of a favorable rebirth.

Over the centuries, the emperor’s pilgrimage was replicated, first by noblemen and samurai. Trails were carved out of rocky hillsides, the more arduous the better, under the assumption that nothing worthwhile ever comes easily. By the 1400s, ordinary folk had begun following the Kumano Kodo. In a time when people didn’t have many opportunities to travel, a pilgrimage became an acceptable way for young people to escape home.

“They strapped tatami mats on their backs for bedding and set off in search of blessing,” says Tetsuo, explaining life on the trail 600 years ago. “They were in search of adventure. Maybe even in search of the opposite sex. The Kumano Kodo offered a rare chance to see the world.”

Think of it as the 15th-century answer to the modern-day gap year.

The trail made famous by Emperor Uda is the Nakahechi, or Imperial Route, and it remains the most popular of the Kumano trails. UNESCO’s decision in 2004 to award the Kumano Kodo a spot alongside the Way of St. James as the only registered World Heritage List pilgrimage routes brought the trail to the attention of non-Asians for the first time.

Hike the Kumano Kodo today and you’ll see remnants of Kumano’s 15th-century glory days: the tumbledown walls of long-abandoned trailside inns and teahouses; the still-brilliant red torii gates symbolizing a traveler’s passage from the secular to the sublime; and small subsidiary shrines like that moss-covered Buddha.

But this pilgrimage route merits a visit for more than spiritual reasons. The Kumano Kodo also ranks as one of the world’s loveliest nature hikes. Rocky promontories reveal sweeping vistas of the blue-gray Kii Mountains and glimpses of gushing waterfalls, including Japan’s tallest, the 436-foot Nachi-no-Otaki. In springtime, delicate cherry blossoms dot the path. In autumn, maple trees blaze red and orange. Even Emperor Uda must have relished the natural spectacle of this corner of Japan.

Today’s hikers — an estimated 10,000 annually — relish this off-the-beaten-path Japan all the more for its disparity with the country’s more familiar haunts. Bamboo forests and the occasional rice field stand in stark contrast to the glass-and-steel skyscrapers and multistory video screens visitors have come to expect in cities like Tokyo.

And then there’s the cultural insight. Along the Kumano Kodo, modest but comfortable Buddhist temples and traditional family-run ryokan inns offer accommodation as it used to be across all of Japan. Dinner trays arrive crowded with small bowls, each containing morsels of the day’s local cuisine: dried and grilled fish; pickled plums; crisp seaweed salads and slippery noodles; tofu served up a dozen different ways.

Of universal interest are the Kii Peninsula’s ubiquitous natural hot springs, or onsen, typically available at lodging along the Kumano Kodo. Once used by ancient travelers for ritual religious purification, the springs provide for modern travelers a pre-dinner bath and long, therapeutic soak, a welcome balm for weary legs and aching muscles.

Along the route, the Kumano Sanzan, the three grand shrines of the Kumano Kodo, draw a quiet respect from visitors. Built of giant cypress beams taken from the surrounding forest, the shrines often give the appearance of having simply sprung from their environment. Deeply curved rooflines measure 2 feet thick. The Kumano Kodo’s symbol of a three-legged crow adorns paper screens and souvenir amulets. And the smell of incense fills the air.

Visitors of all backgrounds, devout religious adherents and culture-loving hikers approach, one by one. After ringing a brass bell and clapping, they bow deeply to pay their respects and ask for a blessing.

After 1,000 years, the prayers seem likely to continue.

Amy S. Eckert is a freelance writer.