Shimabara-shi

In the latest Population Census the population is about 43,000 (43,338 in 2020). This city’s population has a step from a merger. Shimabara City incorporated Ariake Town on 2006-1-1 to reach its present city area. The former Shimabara City before the incorporation, at 39,605 in 2000 and 38,316 in 2005, became 47,455 in 2010 with Ariake Town added, and from there, through the 45,436 of 2015 to the 43,338 of 2020, it has fallen gently after the incorporation.

Looking inside, the figure peculiar to a city of the Shimabara Peninsula appears. The share aged 65 and over reached 35.8% in 2020, well over three in ten. The household-with-children share is 20.0%, and the Childcare Waitlist was zero in both 2024 and 2025. The Fiscal Capacity Index was 0.42 in fiscal 2023 — its own tax revenue does not reach half of expenditure, and the reliance on the allocation tax is large. The figure shows in the numbers: a town of castle, volcano and water, losing population and deepening its aging after the incorporation, while keeping the waitlist at zero. Why it takes this form cannot be read without going back to the past of Shimabara Castle and the Shimabara Rebellion.

The urban area of Shimabara stands upon land caught between the Ariake Sea and Mount Unzen, and upon the heavy past that castle and volcano inscribed. At the beginning of the Edo period, Matsukura Shigemasa built Shimabara Castle from around 1618. But this castle was so large as to be out of all proportion to the domain’s rice yield, and its construction broke the Matsukura family’s finances. To make up the finances, unprecedentedly harsh taxation was laid on the people, and the persecution of Christians who refused to convert was layered on top.

That harsh rule invited a great uprising. From 1637 to the next year, the people of Shimabara and Amakusa rose in large-scale armed revolt against the harsh taxation and persecution — the Shimabara Rebellion. It was inscribed in history as one of the largest uprisings through the Edo period. The castle’s disproportionate size broke the finances, made the taxation harsh, and invited the uprising — the causality of politics and finance chained itself in this land.

And the volcano, too, inscribed disaster upon this land. In 1792, with the eruption of Mount Unzen, Mount Mayuyama collapsed; its debris flowed into the Ariake Sea and raised a tsunami, and on both the Hizen and Higo shores more than fifteen thousand lives were lost in all — the disaster called "the Shimabara Catastrophe, the Higo Calamity." On the other hand, this volcanic land stores abundant water underground and became also a "city of water," with clear water welling up all over the town. The Shimabara spring-water group was selected as one of the Hundred Famous Waters in 1985. The castle broke the finances, the uprising arose, the volcano brought disaster and water — this town’s form stands upon the heavy past borne by the geography of land caught between the Ariake Sea and Mount Unzen.

What characterizes Shimabara is that, while it holds the heavy past of castle and volcano, it is losing population and deepening its aging after the incorporation. From 2010, after the incorporation, to 2020, some four thousand were lost, and the share aged 65 and over rose to 35.8%. In the Shimabara Peninsula, a land cut off from the mainland’s cities by sea and mountain, amid the flow of the younger generation moving to cities such as Nagasaki and Fukuoka, the fall of population and the deepening of aging can be read as occurring at once.

On the other hand, the household-with-children share is kept at 20.0%, and the Childcare Waitlist has moved at zero. This can be read as an expression of how local industry and agriculture on the peninsula have tied a certain number of young households here. The Fiscal Capacity Index of 0.42 is a level that does not reach even half of expenditure with its own tax revenue, with a large reliance on the allocation tax. It reflects that, against the expenditure that supports a peninsular city, the tax source is limited. The town of castle, volcano and water now loses population and deepens its aging, while keeping the waitlist at zero, its finances supported by the allocation tax. The population falls, the aging passes well over three in ten, the body of the finances is weak. Yet the waitlist is zero and the household-with-children share holds at two in ten. A falling indicator and a kept indicator stand at once in this land, the Shimabara Peninsula.

In Shimabara, the past that castle and volcano inscribed is layered. One is the past of Shimabara Castle, which Matsukura Shigemasa built and whose construction broke the finances and invited the Shimabara Rebellion, holding an origin in which the causality of politics and finance chained itself. Another is the character of a volcanic land where Mount Mayuyama collapsed in the Shimabara Catastrophe of 1792, holding the memory of disaster. And the Shimabara spring-water group, selected as one of the Hundred Famous Waters, gives this town the face of a "city of water," with clear water welling up in a volcanic land.

Shimabara is a town of castle, volcano and water, caught between the Ariake Sea and Unzen. From the land of Shimabara Castle and the Shimabara Rebellion, to the volcanic land where Mount Mayuyama collapsed, to the city of water where clear water wells up — this peninsular land caught between the Ariake Sea and Mount Unzen has held in one continuous thread the castle, the uprising, the volcano’s disaster, and the clear water. The same volcano has brought to this town both the disaster that takes life and the water that wells up all over the town.