Hashima Island: Japan's Abandoned Battleship Island and Its Dark History

Coal was discovered under the waters around Hashima in 1810, but the real shock is what happened next. A reef-sized rock with no vegetation, no fresh water, and no reason to live there turned into a full-on “battleship” city, stacked so high it looked like the ocean swallowed a neighborhood.

By 1959, Hashima was home to 5,259 people crammed into just 6.3 hectares, with narrow streets, tiny apartments, and a life that ran on industrial schedules. Mitsubishi built reinforced concrete homes, then layered in schools, a hospital, a cinema, a pachinko parlor, and even temples and shrines, because mining still had to keep going. And the dark part, the part people still argue about, is that the city’s comfort depended on extracting coal from under the seabed, nonstop.

The island was engineered to be self-contained, but it was also engineered to be temporary. Wikimedia

Hashima Island History: From Coal Mine to City

Coal was first discovered under the waters around Hashima in 1810. At the time, the island itself was barely more than a reef. A 6.3-hectare rock with no vegetation, no fresh water, and no reason for anyone to live there.

That changed in 1890, when Mitsubishi Goshi Kaisha bought the island and began full-scale industrial coal mining. The undersea coal deposits ran more than a kilometer below the seabed and produced high-quality coal used in steelmaking, particularly for the government's Yawata Steel Works. Coal was so important to Japan's industrial rise during this period that it was called black diamond.

Mitsubishi expanded the island through land reclamation, eventually tripling its original size. To house the growing workforce, the company built Japan's first reinforced concrete apartment building in 1916. A seven-story structure that still stands. Over the following decades, dozens more concrete apartment blocks went up. Schools, a hospital, a cinema, a pachinko parlor, a Buddhist temple, a Shinto shrine. By the 1950s, Hashima was a self-contained vertical city in the middle of the ocean.

An apartment block on the island, 1930

Wikimedia

When Mitsubishi Goshi Kaisha bought Hashima in 1890 and started full-scale mining, the “black diamond” story stopped being a slogan and became a daily grind for the workers moving in.</p>

The Most Densely Populated Place on Earth

At its peak in 1959, Hashima housed 5,259 people on 6.3 hectares of land. That works out to a population density of around 83,500 people per square kilometer, roughly seven times the density of central Paris, and one of the highest population densities ever recorded anywhere.

Life on Battleship Island was claustrophobic but technologically advanced for the era. Despite having no natural water source, the island had Japan's first undersea water supply system, completed in 1957. By 1958, nearly 100% of households owned a television set at a time when TVs cost the equivalent of one to two months of average income. An indicator of how well miners on Hashima were paid relative to the rest of Japan.

Apartments were small. Streets were narrow. Some residents had as little as 1.5 meters of personal living space. But the island worked. Children went to school. Families lived ordinary lives in extraordinary density. Rooftop gardens were planted because there was nowhere else to grow anything.

Wikimedia

The Dark History of Gunkanjima

The version of Hashima's story that appears on tourist brochures usually stops there. The full version includes something the Japanese government has been reluctant to discuss.

During World War II, Japan brought Korean and Chinese forced laborers to Hashima to support the war effort. Conditions for these workers were brutal, far worse than those experienced by the regular Japanese miners. They worked in dangerous undersea shafts with inadequate equipment, lived in segregated quarters, and were not free to leave. The workers themselves gave the island grim nicknames: Jail Island and Hell Island.

This part of Hashima's history became a major international issue in 2015, when Japan attempted to include the island as part of a UNESCO World Heritage Site listing called "Sites of Japan's Meiji Industrial Revolution." South Korea, North Korea, and China objected, arguing that the official recognition without acknowledging the forced labor history was unacceptable.

Japan and South Korea eventually reached a compromise: UNESCO would approve the listing if Japan agreed to "incorporate appropriate measures" to remember the victims, including an information center documenting the forced labor. The site was approved on July 5, 2015.

The agreement immediately fell apart. The same day UNESCO approved the listing, Japan's Foreign Minister Fumio Kishida publicly rejected the term forced labor, claiming workers were instead "requisitioned against their will." UNESCO has continued to press Japan to fully acknowledge the history. The dispute remains unresolved.

This feels like Sarah Winchester’s mansion-building frenzy after her husband’s death, where tragedy shaped every room.

Ruins of the mine

Wikimedia

The numbers get wild at the peak in 1959, when 5,259 people crowded into 6.3 hectares, and even the undersea water supply system and near-universal TVs could not fix the claustrophobia.</p>

Why Hashima Island Was Abandoned

Hashima's downfall came not from disaster but from energy economics. In the post-war decades, Japan transitioned from coal to oil as its primary energy source. Coal demand collapsed. By the early 1970s, Hashima's mines were no longer economically viable.

The mine officially closed on January 15, 1974. By April 20 of the same year, every single resident had left the island. The departure was sudden, apartments were left with furniture still inside, dishes still in cupboards, possessions scattered as though residents intended to come back. They didn't.

For the next 35 years, Hashima was off-limits to the public. Mitsubishi maintained ownership until 2002, when the company transferred it to the town of Takashima, which was later absorbed by Nagasaki City. Typhoons battered the island year after year. Concrete spalled and crumbled. Steel reinforcement rusted through. The buildings began collapsing, and Nature started reclaiming the place at a slow but visible pace. The History Channel's Life After People featured Hashima in 2009 as a real-world example of how quickly modern construction decays without maintenance, even after just 35 years.

Location

Wikimedia

By the time people were watching TV in apartments with no natural water source and walking past cinema nights and pachinko lights, the island’s whole purpose was still tied to coal running out.</p>

Visiting Battleship Island Today

In 2009, after Nagasaki City built designated visitor walkways and reinforced the most dangerous structures, tours to Hashima reopened. You can't wander the island freely. The areas accessible to visitors are limited to short observation platforms, and even those can collapse without warning, which is why tours are routinely cancelled in poor weather.

The only way to reach Hashima is through one of several organized boat tours departing from Nagasaki Port. The crossing takes about 30 minutes each way. Most tours include a documentary screening before arrival to explain the island's history. On-island time is about 45 minutes across three observation points. The whole trip takes around three hours including travel.

January 15, 2024 marked the 50th anniversary of Hashima's closure. Former residents gathered at the Gunkanjima Digital Museum in Nagasaki to commemorate the date. Many of them spent their entire childhoods on the island and still describe it not as the eerie ruin it has become, but as the place where they grew up.

Hashima is now a UNESCO World Heritage Site, but only specific parts of it are technically listed. The seawall and the undersea coal mine. The crumbling apartment blocks that make the place visually unforgettable are not part of the official heritage protection, and their future is uncertain.

The island will eventually fall into the sea entirely. Estimates vary on how long the remaining structures can hold, but no one expects them to last another fifty years.

For now, Hashima sits in suspended animation. A city paused in 1974, slowly being eaten by the ocean it was built on.

Other places carry the same kind of weight where industrial history and quiet collapse meet: Poveglia Island in Venice has its own layered past as a plague station turned mental hospital, and the Door to Hell in Turkmenistan shows what happens when human industry leaves a permanent mark on the landscape.

The Winchester Mystery House belongs to a softer category, preserved rather than abandoned, but plays into the same fascination with frozen-in-time architecture.

Postize has covered other examples of nature reclaiming abandoned places, and the shipping container architecture movement shows how industrial materials get adapted for new uses long after their original purpose has expired. Hashima just happens to be the most dramatic example we have.

He might be happier in a different apartment, because Hashima was built to keep working until it couldn’t.

Before you judge the “dark history” of Hashima, see how one artist turned the ocean into a gallery. One artist built a “sea gallery,” where the ocean acted as curator and co-creator.