Kei Ito, who runs a mountain villa in Toyama Prefecture, central Japan, has been toiling to restore a legendary hiking trail celebrated for providing access to "hellish" landscapes that are on many adventure seekers' dream lists.

The Ito Shindo trail is dubbed "the last frontier of the Northern Alps" and links Toyama and Nagano prefectures. Committing to fulfill the dying wish of his late father Shoichi Ito, after whom the trail is named, Kei, 45, has tried to re-establish the path on which "people can experience nature directly."

Kei Ito, who runs the Mitsumata-sanso mountain villa in Toyama Prefecture, central Japan, is pictured in December 2022. (Kyodo)

Roughly 10 kilometers long, the Ito Shindo connects Yumata hot springs in Omachi, Nagano Prefecture, at the bottom of the trail and Mitsumata-sanso, the villa run by Ito, which was privately funded, built and maintained by his father until 2016.

After World War II, the elder Ito became fascinated by the Kurobe River headwaters and wild natural scenery in the surrounding area and bought a run-down mountain lodge, which he later turned into Mitsumata-sanso. But to do that, he needed to build an easy route to transport construction materials.

From any departure point, it would have taken at least two days to walk to the villa, located at an altitude of about 2,550 meters, but the journey was cut to one day by using the Ito Shindo, a route thoroughly researched by Shoichi before construction commenced in 1953. After the route's opening in 1956, as many as 500 people would traverse it some days.

But when the groundwater started to rise due to the development in 1971 of a nearby dam, the ground became unstable, resulting in the collapse of parts of the trail. Metal on the suspension bridges also corroded from the sulfur dioxide that spewed from a nearby volcano, and by around 1983 the path was near impassable.

Mountain hikers traverse the Ito Shindo route in Nagano Prefecture, central Japan, where blue water flows between reddish-brown rocks in 2019. (Courtesy of Mitsumata-sanso)(Kyodo)

A mountain hiker bounds across a river on the Ito Shindo route in Nagano Prefecture, central Japan, in August 2022. (Courtesy of Mitsumata-sanso)(Kyodo)

Kei, who grew up going back and forth between his home in Tokyo and the Northern Alps, was a freshman in high school when he first trekked the Ito Shindo.

Hot spring sediments accumulated on the riverbed in the shape of volcanic cones from which steam rose in various locations, while clear blue hot spring water flowed between the reddish granite rocks to complete the painting-like scenes. Moss did not grow there, and in places, dead serows that had inhaled poisonous gas lay on the rocks.

"It was shocking to see the hellish beauty created by the lack of life," he recalled.

Shoichi's only desire before his death at age 93 in 2016 was to restore the Ito Shindo. His son also wanted people to walk the "world of death" again and started crowdfunding to rebuild suspension bridges, among other parts of the trail, last May.

His ambitious project created a stir on the internet. Nearly 13.6 million yen ($103,000) was collected from close to 1,000 people, far exceeding the target amount. By October, he had completed three suspension bridges using corrosion-resistant materials.

Keisuke Kobayashi, 86, a former employee of the mountain villa who was in charge of maintenance of suspension bridges and other parts of the route in the 1970s until the trail's closure, is one person keenly awaiting its grand reopening this summer.

"It's a place you can see scenery that makes you wonder, 'Is this really Japan?' When it opens I think it will be flooded by young people," Kobayashi, who hails from the ski resort town of Hakuba in Nagano Prefecture, said.

In the rebuilding process, Ito worked hard to create a trail that would be "adventurous" by intentionally leaving places for hikers to find their own way. The plan is to construct hut shelters and other facilities in preparation for the trail's full-scale reopening in August.

Ito says he plans to enhance the offering by including guides to accompany seniors and beginners so they can travel safely. "I believe that the trail revival project will act as a catalyst to encourage mountain tourism in the region," Ito said.

A mountain hiker crosses a completed suspension bridge on the Ito Shindo route in Nagano Prefecture, central Japan, in August 2022. (Courtesy of Mitsumata-sanso)(Kyodo)

People transport building materials along the Ito Shindo route in 1957 after its opening. (Courtesy of Mitsumata-sanso)(Kyodo)

Mt. Yarigatake (upper left) seen from the Ito Shindo trail in photo taken in 2021. (By photographer Mika Inoue)(Kyodo)