Coal was first discovered on the island around 1810, and the island was continuously inhabited from 1887 to 1974 as a seabed
coal mining facility.
Mitsubishi Goshi Kaisha bought the island in 1890 and began extracting coal from undersea mines, while seawalls and land reclamation (which tripled the size of the island) were constructed. Four main mine-shafts (reaching up to a kilometre deep) were built, with one actually connecting it to a neighbouring island. Between 1891 and 1974, around 15.7 million tons of coal were excavated in mines with temperatures of 30 °C and 95% humidity. In 1916, the company built Japan's first large
reinforced concrete building (a 7-floor miner's apartment block), to accommodate their burgeoning ranks of workers. Concrete was specifically used to protect against
typhoon destruction. Over the next 55 years, more buildings were constructed, including apartment blocks, a school, kindergarten, hospital, town hall, and a community centre. For entertainment, a clubhouse, cinema, communal bath, swimming pool, rooftop gardens, shops, and a
pachinko parlour were built for the miners and their families. Beginning in the 1930s and until the end of
World War II, conscripted Korean civilians and Chinese prisoners of war were forced to work under very harsh conditions and brutal treatment at the Mitsubishi facility as
forced labourers under Japanese wartime mobilisation policies. During this period, many of these conscripted labourers died on the island due to various dangers, including underground accidents, exhaustion, and malnutrition; 137 died by one estimate; about 1,300 by another. In 1959, the island's population reached its peak of 5,259, with a
population density of 835 people per
hectare (83,634 people/km2, 216,264 people per square mile) for the whole island, or 1,391 per hectare (139,100 people/km2) for the residential district. As
petroleum replaced
coal in Japan in the 1960s, coal mines began shutting down across the country, and Hashima's mines were no exception. Mitsubishi officially closed the mine in January 1974, and the island was cleared of inhabitants on 20 April. Today, its most notable features are the abandoned and still mostly-intact concrete apartment buildings, the surrounding
seawall, and its distinctive profile shape. The island has been administered as part of
Nagasaki city since the merger with the former town of
Takashima in 2005. Travel to Hashima was re-opened on 22 April 2009, after 35 years of closure. ==Current status==