This land is made up of many islands. Once it was cut off from the mainland by the sea, but a little over half a century ago, from the tip of a mainland peninsula, island by island, five bridges were built. The bridges joined island to island and tied mainland and island by a single road. In the sea where the bridges are built, small islands dot the water, and a scene of growing pines spreads. This land of islands and bridges, having bound four towns into one and been established as a city, has greatly lost population after the merger. In that fall of population is a reason peculiar to the land of islands. Kamiamakusa’s numbers are the record of a town in which five bridges and a merger of four towns are inscribed.
A city that opens in the east of the Amakusa Islands of Kumamoto Prefecture, on a land made up of many islands. Because this city was established in 2004 by binding four towns anew into one, its population statistics as a city cover the period from 2005, after the establishment, on. From the 32,502 of 2005 to the 24,563 of 2020, it has greatly decreased. What I (Atlas) want to read here is not the sign "a city of Amakusa," but the causal thread: how the past of five bridges and a merger of four towns is translated into today’s population and finances.
01 · Seeing the present Kamiamakusa in its numbers
In the latest Population Census the population is about 25,000 (24,563 in 2020). Because this city was established in 2004 by binding four towns anew into one, its population statistics as a city cover the period from 2005, after the establishment, on. From the 32,502 of 2005, through the 29,902 of 2010 and the 27,006 of 2015, to the 24,563 of 2020, some eight thousand have been lost over fifteen years.
Looking inside, the figure of a city made up of islands greatly raising its age appears. The share aged 65 and over rose from 37.5% in 2015 to 42.0% in 2020, passing four in ten. The household-with-children share is 15.4% (2020), and the crude birth rate is 5.8 per thousand in 2020. The Childcare Waitlist was zero in both 2024 and 2025. The Fiscal Capacity Index was 0.25 in fiscal 2023 — a level able to cover only a quarter of expenditure with its own tax revenue, with a large degree of reliance on the local allocation tax. The figure shows in the numbers: a land of islands and bridges, greatly losing population and deepening its aging after the merger. Why it takes this form cannot be read without going back to the past of the islands, the five bridges, and the merger of four towns.
Source: Population Census (Statistics Bureau, MIC) / Local Government Finance Survey, Fiscal Capacity Index (MIC) / Childcare Facility Status Report (Children and Families Agency) / Real Estate Information Library (MLIT)
02 · Islands cut off by the sea, five bridges, a sea where pines float, a merger of four towns — the history behind the numbers
What supports Kamiamakusa’s past is the landform of islands cut off by the sea, the five bridges linking mainland and islands, the sea where pines float, and the merger of four towns. The oldest layer is the islands cut off by the sea. This land is made up of many islands in the east of the Amakusa Islands, and once it was cut off from the mainland by the sea. The landform of islands cut off by the sea is this town’s foundation.
This separation by the sea the bridges joined. A little over half a century ago, from the tip of a mainland peninsula, island by island, five bridges were built. The bridges joined island to island and tied mainland and island by a single road. In the sea where the bridges are built, small islands dot the water, and a scene of growing pines spreads. The path to becoming a city also reflects this town. In 2004, the four towns of the islands were bound anew into one, and the present city was established. The islands cut off by the sea, the five bridges linking mainland and islands, the sea where pines float, and the merger of four towns — the land that piled these four layers is the present Kamiamakusa.
Source: Kamiamakusa City / the Five Bridges of Amakusa (the "Amakusa Pearl Line," which links the mainland to Oyano Island, the Amakusa Matsushima and on to Kamishima Island from Misumi at the tip of the Uto Peninsula, opened in 1966 — overview) / Kamiamakusa City / the islands (located in the east of the Amakusa Islands of Kumamoto Prefecture, made up of Oyano Island and other islands large and small; the Amakusa Matsushima — overview) / Kamiamakusa City (established on 2004-3-31 by the new merger of the four towns of Oyano, Matsushima, Himedo and Ryugatake of Amakusa County; statistics cover the period after the merger, from 2005 — overview)
03 · In the land of islands and bridges, greatly losing population after the merger
What characterizes Kamiamakusa is that, while it holds the past of islands and bridges, it is greatly losing population after the merger. From the 32,502 of 2005, when the city was established, to the 24,563 of 2020, some eight thousand were lost over fifteen years. Even in these islands tied to the mainland by five bridges, one can read that much of the younger generation moved toward the larger cities, and the town’s age as a whole greatly rose. That the share aged 65 and over passed four in ten at 42.0% in 2020 is an expression of that.
On the other hand, the Childcare Waitlist was zero in both 2024 and 2025, the household-with-children share is 15.4% (2020), and the crude birth rate is 5.8 per thousand in 2020. The Fiscal Capacity Index of 0.25 is a level able to cover only a quarter of expenditure with its own tax revenue, showing the large degree of reliance on the local allocation tax seen in common across lands of islands cut off by the sea. The population fell by some eight thousand over fifteen years, the aging passed four in ten, and the body of the finances is thin on tax revenue alone. What overlap of numbers the islands tied to the mainland by bridges have now settled into — that comes into view only when population, age and finances are laid out on a single sheet.
Source: Population Census (Statistics Bureau, MIC) / Local Government Finance Survey, Fiscal Capacity Index (MIC) / Childcare Facility Status Report (Children and Families Agency)
04 · Islands cut off by the sea were tied to the mainland by five bridges
The functions Kamiamakusa holds are not one. There is the past of islands, made up of many islands in the east of the Amakusa Islands and once cut off from the mainland by the sea. There is also the character of five bridges linking mainland and islands, built a little over half a century ago from the tip of a mainland peninsula, island by island. And it holds the face of a sea where pines float, where small islands dot the sea in which the bridges are built and a scene of growing pines spreads. The landform of islands cut off by the sea brought both the five bridges and the scene of the sea where pines float to this land.
Kamiamakusa is a town where islands cut off by the sea were tied to the mainland by five bridges. From the landform of islands, to the five bridges linking mainland and islands, the sea where pines float, and the merger of four towns, what set the skeleton was the geography of "a land made up of many islands in the east of the Amakusa Islands." Even when the bridges tie mainland and island by a single road, the character that the separation by the sea inscribed on the land does not vanish. The convenience of the road across the bridges, and the limits of island living, still coexist in the same city area.
Source: Kamiamakusa City / the Five Bridges of Amakusa (the "Amakusa Pearl Line," which links the mainland to Oyano Island, the Amakusa Matsushima and on to Kamishima Island from Misumi at the tip of the Uto Peninsula, opened in 1966 — overview) / Kamiamakusa City / the islands (located in the east of the Amakusa Islands of Kumamoto Prefecture, made up of Oyano Island and other islands large and small; the Amakusa Matsushima — overview) / Kamiamakusa City (established on 2004-3-31 by the new merger of the four towns of Oyano, Matsushima, Himedo and Ryugatake of Amakusa County; statistics cover the period after the merger, from 2005 — overview)
05 · Atlas’s note — in the land of islands and bridges, reading the island constraint that does not change even when the towns are bound
Lay out Kamiamakusa’s numbers and the indicators of a city made up of islands line up: a population greatly falling after the merger, an aging rate of 42.0%, a household-with-children share of 15.4%, and a fiscal capacity of 0.25. But when I (Atlas), as a certified public accountant, read these, what I want to read here is how this land "crossed the separation of the sea by being tied to the mainland by five bridges a little over half a century ago." The bridges tied mainland and island by a single road and greatly changed island living. But even after being tied to the mainland by bridges, the population keeps greatly falling. The chain in which being tied to the mainland by bridges does not directly connect to the holding of population explains well this town’s numbers.
Another thing I want to consider is that this town, "even after binding four towns, is at the thinness of a fiscal capacity of 0.25." Even binding four small towns of the islands, its own tax revenue alone covers only a quarter of expenditure. The limits of the industry and population of the land of islands show in the thinness of the finances.
Even binding four island towns, the very structure of the land of islands, which limits industry and population, does not change, and shows in the thinness of the finances. Whether to view this land tied to the mainland by five bridges by the convenience of living across the bridges, or to view it as a land of islands still cut off by the sea, changes with where in living one turns one’s eyes. Even tied to the mainland by five bridges, the very structure of the land of islands, which limits industry and population, does not change, and shows in the thinness of a fiscal capacity of 0.25.
Source: Population Census (Statistics Bureau, MIC) / Kamiamakusa City / the Five Bridges of Amakusa (the "Amakusa Pearl Line," which links the mainland to Oyano Island, the Amakusa Matsushima and on to Kamishima Island from Misumi at the tip of the Uto Peninsula, opened in 1966 — overview) / Kamiamakusa City / the islands (located in the east of the Amakusa Islands of Kumamoto Prefecture, made up of Oyano Island and other islands large and small; the Amakusa Matsushima — overview) / Kamiamakusa City (established on 2004-3-31 by the new merger of the four towns of Oyano, Matsushima, Himedo and Ryugatake of Amakusa County; statistics cover the period after the merger, from 2005 — overview)
Editor’s note: all figures and sources are drawn from official statistics. The prose follows Atlas’s voice, and AI (atlas-handcrafted-reverse-v1 (wave34-west 2026-06-04)) handled the shaping of the text. Evaluative or predictive language (such as “a good buy” or “attractive”) is intentionally left out. Revision id: wave34w_