At the center of this town spreads a limestone plateau, one of Japan’s broadest, where upon a grass-covered tableland white masses of limestone show their faces in groups, here and there. Beneath that plateau extends a limestone cave, among the longest in the country, hollowed out by rain that dissolved it over long ages. The limestone above ground was dug out and sent by a long belt to the port to become various materials. In the same mountains, coal too was once dug. This town, the land of karst and limestone caves, became one with two towns near the end of the Heisei era and has lost population. Mine’s numbers are the record of a town etched by the history of a limestone plateau and a mountain of coal.
A city that opens inland in the central part of Yamaguchi Prefecture. Because the population became one with two towns and was founded in 2008, there is a large step before and after that. The value of the former city area before founding was 17,754 in 2005, and from 2010, reflecting the founding, it was 28,630, thereafter falling to 23,247 (2020). The increase from 2005 to 2010 is a step from becoming one with two towns, not the town swelling. What I (Atlas) want to read here is not the sign "a city of the prefecture’s center," but the causal thread: how the history — a limestone plateau and a mountain of coal — is translated into today’s population and finances.
01 · Seeing the present Mine in its numbers
In the 2020 Population Census, this city’s population is 23,247 — thinned to a little over twenty thousand. Because this city became one with two towns and was newly founded in 2008, care for that step is needed when reading the population course. The former city area before founding was 18,638 in 2000 and 17,754 in 2005. From 2010, reflecting the founding, it was 28,630, and thereafter it fell on the post-founding city area to 26,159 in 2015 and 23,247 in 2020.
Looking inside, the figure of a limestone-and-coal mountain land raising its age greatly appears. The share aged 65 and over was 42.6% in 2020, passing four in ten. The household-with-children share was 14.6% in 2020, and the crude birth rate was 3.5 per thousand in 2020. The Childcare Waitlist was zero in both 2024 and 2025. The Fiscal Capacity Index was 0.39 in fiscal 2023 — a level able to cover only about four-tenths of expenditure with its own tax revenue. The figure of the land of karst and limestone caves, losing population after becoming one with two towns, appears in the numbers. Why it takes this shape cannot be read without going back over the history of a limestone plateau and a mountain of coal.
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 · The karst plateau, the limestone cave below, the mountain of limestone and coal, the merger with two towns — the history behind the numbers
This town’s history can be traced, with a limestone plateau as the starting point, to the limestone cave below, the digging of limestone and coal, and the merger with two towns. The first layer is the limestone plateau. At this city’s center spreads a limestone plateau, one of Japan’s broadest, where white limestone shows its face in groups upon a grass-covered tableland. Beneath it extends a limestone cave, among the longest in the country, hollowed out by rain over long ages. The limestone plateau and the cave below were this town’s foundation.
This limestone was dug out and used. The limestone above ground was quarried and sent by a long belt to the port to become a material for cement and the like. In the same mountains, coal too was once dug. Two blessings of the earth, limestone and coal, supported this land’s livelihood. The road by which it became a city mirrors this town, too. In 2008, late among the Heisei mergers, the former Mine City and two towns became one and were newly founded. The limestone plateau, the limestone cave below, the mountain of limestone and coal, and the merger with two towns — Mine’s present continues from this history of limestone and coal, etched by the limestone plateau hollowed by rain.
Source: Mine City / Akiyoshidai and Akiyoshido (the Akiyoshidai karst plateau, one of Japan’s largest expanses of limestone, and Akiyoshido spreading beneath it; one of Japan’s three great karsts; the Mine-Akiyoshidai Geopark — overview) / Mine City / limestone and coal (the limestone of Akiyoshidai is quarried and sent by a long-distance belt conveyor to the port to become the raw material for cement and the like; coal was also mined at the Omine coalfield — overview) / Mine City (inland, in central Yamaguchi; formed on 2008-03-21 by the new merger of the former Mine City plus Akiyoshi and Mito towns of Mine District; the statistics move greatly in 2010 — overview)
03 · In the land of karst and limestone caves, becoming one with two towns and losing population
What characterizes Mine is that, while bearing the history of limestone and coal, it has lost population after becoming one with two towns. On the post-founding city area, more than five thousand fell over ten years, from 28,630 in 2010 to 23,247 in 2020. Even in these mountains supported by limestone and coal, one can read that the end of coal-digging and a part of the young generation moving toward larger cities overlapped, and the age of the whole town rose greatly. That the share aged 65 and over passed four in ten at 42.6% in 2020 is one expression of this.
Meanwhile the Childcare Waitlist was zero in both 2024 and 2025, the household-with-children share was 14.6% in 2020, and the crude birth rate was 3.5 per thousand in 2020. The Fiscal Capacity Index of 0.39 is a level able to cover only about four-tenths of expenditure with its own tax revenue. The land of karst and limestone caves now walks on, losing population, just so on the city area that became one with two towns. A population that fell by more than five thousand after the founding, aging above four in ten, and finances covering only four-tenths on tax revenue — these three are three faces of the same single shrinking of a limestone-and-coal mountain land, where coal-digging ended and the young generation slipped out to the cities. Watch only the aging rate, and one cannot follow how the end of the underground coal mine moved the numbers of these mountains.
Source: Population Census (Statistics Bureau, MIC) / Local Government Finance Survey, Fiscal Capacity Index (MIC) / Childcare Facility Status Report (Children and Families Agency)
04 · A mountain land where coal-digging ended and the age rises
At Mine’s center, a single limestone-rock plateau holds two blessings of differing character above and below ground. It holds the history of a limestone plateau, one of Japan’s broadest, where white limestone shows its face in groups upon a grass-covered tableland. It also holds the character of a cave below, where rain has hollowed out one of the longest limestone caves in the country. And it holds the face of a limestone-and-coal mountain land, digging out the limestone above ground and once digging coal as well.
Mine is a town where a limestone plateau hollowed by rain came to hold the cave below and the mountain of coal. From the karst plateau, to the limestone cave below, the mountain of limestone and coal, and the merger with two towns — the geography of "a limestone plateau, one of Japan’s broadest" hollowed a long limestone cave below, came to hold the digging of limestone and coal, and shaped the town’s outline. Above ground, limestone to dig out and use; below ground, a limestone cave to visit and see. The same single bedrock bears at once two blessings of opposite direction, an industrial material and a scenery that calls people — Mine’s outline is made of both its front and its back.
Source: Mine City / Akiyoshidai and Akiyoshido (the Akiyoshidai karst plateau, one of Japan’s largest expanses of limestone, and Akiyoshido spreading beneath it; one of Japan’s three great karsts; the Mine-Akiyoshidai Geopark — overview) / Mine City / limestone and coal (the limestone of Akiyoshidai is quarried and sent by a long-distance belt conveyor to the port to become the raw material for cement and the like; coal was also mined at the Omine coalfield — overview) / Mine City (inland, in central Yamaguchi; formed on 2008-03-21 by the new merger of the former Mine City plus Akiyoshi and Mito towns of Mine District; the statistics move greatly in 2010 — overview)
05 · Atlas’s note — reading Mine from the front and back of a single bedrock
Lay out Mine’s numbers and the indicators of a limestone-and-coal mountain land raising its age line up: a population falling after the merger, an aging rate of 42.6%, a household-with-children share of 14.6%, and a fiscal capacity of 0.39. In the eye of an accountant who has read the front and back of ledgers, what I want to read here is the front and back of a single plateau — that this town "holds together, within the same earth, two opposing values: above ground, a mountain of limestone to dig out and use, and below ground, a limestone cave hollowed by rain that one would wish to keep." The limestone to dig and use, and the cave below to visit and see, are two blessings of differing direction born of the same limestone land. The chain, in which a single resource holds two faces, an industrial material and a scenery that calls people, shows a thickness that does not appear in this town’s numbers.
The other thing I want to consider is that this town’s population step "arises from a merger in 2008, a late time among the Heisei mergers." While many cities widened their city area by mergers around 2005, this town became one with two towns a little later. So the year in which the population step appears is also a little shifted from other cities. The reading that the difference in the merger’s timing changes the way the statistical step appears cannot be grasped while merely viewing the population figures as a single line. Read with the sign "a city of the prefecture’s center," or read as "a town where a limestone plateau hollowed by rain holds the cave below and the mountain of coal" — the way the same bedrock looks changes. The limestone above ground, to dig and use, and the cave below, to visit and see, I would read side by side as the front and back of the same bedrock. That the population step arose in the late 2008 merger and that the year the step appears is shifted from other cities, too, will be missed, and the course misread, if overlooked. What I can say is as far as the placing of the fact of the front and back of limestone rock; how to translate it into living, I do not step into.
Source: Population Census (Statistics Bureau, MIC) / Mine City / Akiyoshidai and Akiyoshido (the Akiyoshidai karst plateau, one of Japan’s largest expanses of limestone, and Akiyoshido spreading beneath it; one of Japan’s three great karsts; the Mine-Akiyoshidai Geopark — overview) / Mine City / limestone and coal (the limestone of Akiyoshidai is quarried and sent by a long-distance belt conveyor to the port to become the raw material for cement and the like; coal was also mined at the Omine coalfield — 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 (wave-cs1 2026-06-05)) handled the shaping of the text. Evaluative or predictive language (such as “a good buy” or “attractive”) is intentionally left out. Revision id: wavecs1_