AIRCO VELHO, Brazil >>Shigeru Nakayama, the guardian of this ghost city in the Amazon rain forest, gazes at the Rio Negro, a vast blackwater tributary. From some angles, it looks less like a river than a sea, spurring him to remember Japan.

“Fukuoka got kind of cold during winter,” said Nakayama, 66, who left the island of Kyushu in southern Japan with his parents and three brothers in the mid-1960s for a new life in Brazil. “We were farming people, trying to get ahead. Japan was reduced to ashes after the war. Life was still tough.”

“But Brazil was the land of our dreams,” said Nakayama, squinting under the punishing midday sun as he leaned his wiry frame against one of the crumbling stone buildings of Airco Velho — a town so overgrown and forlorn it is now held in a labyrinthine embrace of tree roots and vines.

If anyone in this remote corner of the Amazon can attest to how dreams unfold in unanticipated ways, Nakayama certainly can.

But first, when visitors wash up at the ruins of Airco Velho, he prefers to politely engage them with a bit of history, in his Japanese-accented Portuguese, about the enigmatic outpost he has vowed to protect.

Indigenous peoples inhabited the region for thousands of years, leaving their mark in nearby petroglyphs, Nakayama pointed out. More recently, slaving expeditions from Sco Paulo penetrated the far reaches of the Amazon in the 17th century, wreaking genocidal havoc among tribes living along the Rio Negro.

The Portuguese then founded a proselytizing outpost at this spot in 1694, which they called Santo Elias do Jaz, putting down stakes in the huge tropical forest coveted by both Portugal and Spain. Historians say this Amazonian settlement predated the better-known cities of southeast Brazil in the colonial era like Ouro Preto and Sco Joco del Rei, established in the early 18th century.

Missionaries went about competing for souls here, delivering sermons to indigenous people in a stone church for the better part of two centuries. Before Brazil gained its independence in 1822, the authorities in distant Lisbon changed the name of the settlement to Airco, which persisted on maps as a tiny dot on a vast frontier.

Nakayama dwells on such details after easing open the door to the hovel with dirt floors where he lives. A racy poster on the wall near the entrance, which features a brunette, scantily clad and grasping a spear while astride a tiger, hangs alongside a road map of Brazil (though this heavily forested region has almost no roads; boats provide most transportation).

In one of the hovel’s rooms, Nakayama has created a museum of sorts to honor Airco Velho. He arrived here in 2001 after homesteading in a nearby part of the Amazon where the authorities created a national park, evicting settlers. Around that time, a descendant of the Bizerra clan, which used to control Airco Velho, asked Nakayama to care for the abandoned outpost.

An oil painting in his museum depicts what Airco Velho might have looked like in its heyday during the Amazon rubber boom in the late 19th and early 20th centuries, when the settlement emerged as a busy hub for rubber tappers and traders.

Hundreds of people are thought to have lived here at the outpost’s height, strolling down cobblestone streets past imposing colonial-style trading houses, shops and municipal buildings, shielded from the tropical deluges under roofs made of Portuguese tile.

Fading photographs of the Bizerras, as if part of a conceptual art piece, capture a family sanguine about their sway in this hinterland.

“This was the law back then,” said Nakayama, grasping a rusting rifle he scavenged from the ruins.

The aging settler knows about justice on Brazil’s frontiers. After leaving Japan, his family moved to Belim, the capital of the large state of Para, in one of the last throes of Japanese emigration to Brazil, an exodus that created what is thought to be the largest population of Japanese and their descendants outside Japan.

Nakayama exudes pride when describing the feats of his countrymen who also followed their star to the Amazon, pointing to the pioneering farming colony of Tomi-Agu. For a stretch when he was younger, Nakayama tried living in Sco Paulo, where far more Japanese made their home, but he felt the forest’s tug.

“The city didn’t agree with me, and I didn’t agree with the city,” he said, explaining that he viewed tropical agriculture as his calling even as his siblings prospered in urban business ventures.

Before Nakayama made his way to Airco Velho, where visitors to the ruins call him “the hermit of the jungle,” his existence was not always so lonely. He had two female companions in the past, he said. The last one, a schoolteacher, died of an unknown disease around the time he decided to make his life here. He does not have any children.

At first, Airco Velho, about several hours by boat from the city of Manaus, was not so desolate. While residents had gradually abandoned the outpost after the rubber boom, a few families had tried to repopulate the city. A schoolhouse for children from nearby communities offered some vitality to Airco Velho.

But like those eerie images of the abandoned sites near the Ukrainian city of Chernobyl, the schoolhouse now stands empty, despite scribbling still on the chalkboard and textbooks casually strewn on the floor as if pupils were simply on a yearslong field trip.

Wielding a machete, Nakayama continues to clear the foliage around the building in an effort to preserve a tidy appearance.

“I’m glad there’s someone taking care of Airco Velho,”said Victor Leonardi, a historian of Amazonia at the University of Brasilia who explored the ruins here in the 1990s. “It smelled of jaguar urine back then, but it was obviously a place of riches at one point, where people dined on porcelain from England and consumed cognac from France.”

There is a lot of down time involved in being a hermit in the Amazon. An electric generator and antenna allow Nakayama to watch some television; he likes to follow the games of Flamengo, his soccer team. He hunts some game for his own consumption like paca, a tasty piglike rodent. He tends a small vegetable garden.

“I’ve never been to the hospital in my life,” said Nakayama, licking his lips after polishing off a plate of tracaja, or yellow-spotted sideneck turtle.

Taking a drag on a Euro cigarette, he amended that statement.

“Well, there was that time when a pit viper bit my wrist and I went to the doctor in Novo Airco,” he added. “He told me I would have lost my arm if I hadn’t gone to see him.”

As he gets older, Nakayama said, he now spends a few days each month in a somewhat less remote settlement called Novo Airco, visiting friends and stocking up on a few supplies, which he buys with a meager government pension for older people. But when a spirited traveler or academic researcher passes through Airco Velho, he is usually available to show them around.

A Japanese film crew recently visited him to do a piece about his spartan existence, which he described as “normal.”

“Japan has turned into a new kind of prosperous country, and I guess that’s good for the people there,” Nakayama said. “But that kind of life was never in the cards for me.”

Nakayama acknowledged that shielding Airco Velho from the encroachment of the jungle was an uphill struggle. A glance around suggests that the strangler figs have the scales tipped in their favor. Amid the ruins, wasps hover; fire ants march; cicadas sing.

The emptiest place of all in Airco Velho might be the cemetery, where many of the gravestones have been made illegible by the passage of the years. Once grandiose stone tombs now lie crumbling, their fragments enveloped in moss.

Still, Nakayama feels the need to clean the graveyard, hacking away at the growth that threatens to devour the site once and for all.

“For centuries, people lived and died in Airco Velho,” he said. “They were the true pioneers, and I have to honor their memory by preserving this place. It is a matter of respect.”

© 2015 The New York Times Company