Niihama-shi

In the latest Population Census the population is about 116,000 (115,938 in 2020). This city’s population, rather than a step from a large merger, has fallen gently by more than ten thousand over twenty years — from 125,537 in 2000 to 123,952 in 2005, 121,735 in 2010, 119,903 in 2015, 115,938 in 2020. It is the curve of an industrial city opening upon the Seto Inland Sea shrinking gently.

Looking inside, aging advances. The share aged 65 and over reached 32.2% in 2020, passing three in ten. The household-with-children share was 19.1%, and the Childcare Waitlist was zero in both 2024 and 2025. The Fiscal Capacity Index was 0.76 in fiscal 2023, a level — high for a regional city — able to cover nearly eight-tenths of expenditure with its own tax revenue. The figure of the town of the Besshi copper mine, losing population and deepening aging while keeping its fiscal strength high, appears in the numbers. Why it takes this shape cannot be read without going back over the history of the Besshi copper mine and Sumitomo.

Niihama’s skeleton is set by a single copper mine that lay in the mountains to the south of the city. The Besshi copper mine was discovered in 1690 and opened the next year, 1691. Thereafter this mine was managed consistently by Sumitomo, and until its closure in 1973 it was mined for fully 283 years. A single enterprise managing a single mine for nearly three centuries — a long history with few other parallels.

That mine gave birth to the town itself. The Besshi copper mine, taking in overseas technology from the Meiji era, became one of Japan’s largest copper mines. And from the process of refining the mined copper, a chemical industry arose, a heavy-machinery industry making mining equipment grew up, and forestry to supply pit timber and an electric-power business to provide motive force were derived. A single copper mine called many industries to the shore of the Seto Inland Sea. It is, in economic geography, a typical company town in which related industries agglomerate cored on a key resource. The Besshi copper mine is also held to be the origin of the Sumitomo Group.

And in the present day, the mine itself has long since closed, but the industries derived from it still support the town, agglomerated along the coast of the Seto Inland Sea. Beginning with the mine’s discovery, mined by Sumitomo for 283 years, with chemical and heavy-machinery industries derived — this town’s shape stands upon the history set by a single mine, the Besshi copper mine.

What characterizes Niihama is that, even after the mine itself closed, the industries derived from it go on supporting the town. Over twenty years more than ten thousand fell, and the share aged 65 and over rose to 32.2%. Amid the mine’s closure and the changes of the times around manufacturing, there is a flow of the young generation moving to other cities such as Matsuyama, and one can read that the fall of population and the deepening of aging occur together. On the other hand, in the household-with-children share of 19.1% and the waitlist staying at zero, one can see the remnant of stability left by the workplaces of industry.

The thickness of that industry shows in the fiscal numbers. A Fiscal Capacity Index of 0.76 is a level able to cover nearly eight-tenths of expenditure with its own tax revenue — high for a regional city. It can be read as the expression of the chemical and heavy-machinery industries derived from the Besshi copper mine still agglomerating along the coast and giving thickness to the tax base. The structure is that, even with the mine closed, the industries derived from it support the city’s finances. Over twenty years more than ten thousand fell, and aging passed three in ten at 32.2%. Even so, a high strength of a fiscal capacity of 0.76 remains. That the mine has long since been exhausted yet the fiscal strength is high — explaining this seemingly mismatched combination are the chemical and heavy-machinery industries derived from the mine and left along the coast.

Whichever of Niihama’s remaining industries you trace, it arrives at a single copper mine. One is the origin of the Besshi copper mine, managed consistently by Sumitomo for 283 years, holding the memory of a mine held to be the origin of the Sumitomo Group. Another is the chemical and heavy-machinery industries derived from that mine, leaving the remnant of a company town agglomerated along the coast of the Seto Inland Sea. And facilities conveying the traces of the mine engrave into this town a history of nearly three centuries walked with the mine.

This geography — facing the Seto Inland Sea, holding the Besshi copper mine in the mountains to the south — called in mining that lasted 283 years, from the opening in 1691 to the closure in 1973, and derived chemicals from its refining, heavy machinery from its mining equipment, and forestry from its pit timber. The mine itself has long since been exhausted, but the industry born from it still supports the town, agglomerated along the coast.