This town has long produced a thick cotton cloth dyed blue. With an indigo-dyed face and an undyed white back layered together, this thick cloth closely resembled the work-clothes fabric from across the sea, and domestic denim is handed down as having sprung from here. At its peak in the 1970s, much of the nation’s jeans were woven in this land. While it is a town that weaves thread, this city also holds, in a mountain village to the north, a highland that enacted the nation’s earliest rule to curb the harm of artificial light and has guarded a dark night sky. This weaving land, where domestic denim arose from indigo-dyed thick cloth, absorbed two towns in the Heisei era and has lost population. Ibara-shi’s numbers record a town inscribed with the history of indigo, weaving, and a starry sky.
A city opening onto the southwestern part of Okayama Prefecture, bordering Hiroshima Prefecture to the west. The population stood at 34,817 in 2000, rose to 45,104 in 2005 by absorbing two towns, and then fell to 38,384 in 2020. The increase between 2000 and 2005 is a step caused by the municipal area widening through absorption, not by the town swelling. What I (Atlas) want to read here is not the sign “a city in the prefecture’s southwest,” but the causal thread: how the history — indigo, weaving, and a starry sky — is translated into today’s population and finances.
01 · See the present Ibara-shi in its numbers
In the 2020 Population Census the population of Ibara-shi is 38,384 — about thirty-eight thousand. Because this city absorbed two towns in 2005, reading the change in population calls for care over that step. The 34,817 of 2000 is the value for the old municipal area before absorption, and the 45,104 of 2005 onward is the value for the wider municipal area after it. From there it fell — 43,927 in 2010, 41,390 in 2015, 38,384 in 2020 — within the post-absorption area.
Looking inside the figures, the shape of a weaving town raising its age appears. The share aged 65 and over was 37.4% in 2020, nearing four in ten. Households with children make up 18.6% (2020), and the crude birth rate was 5.0 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 whose own tax revenue covers only about four-tenths of expenditure. The numbers show the weaving land, where domestic denim arose from indigo-dyed thick cloth, losing population after absorbing two towns. Why it takes this shape cannot be read without tracing the history of indigo, weaving, and the starry sky.
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 · Cotton and indigo dyeing, the thick cloth, the origin of domestic denim, the dark-sky highland, the absorption of two towns — the history behind the numbers
This town’s skeleton is set by a weaving tradition that arose from indigo growing, by the thick cloth that became the source of domestic denim, by a highland that guards a dark night sky, and by the absorption of two towns. The opening layer is cotton and indigo. Cotton cultivation began in this land at the end of the Sengoku period, and when indigo growing was added in the Edo period, indigo-dyed cotton cloth became the local specialty. In the Meiji and Taisho eras a thick cotton cloth — an indigo-dyed face and a white back layered together — was woven in great quantity and sent beyond the sea as well. Thick cloth woven with indigo and cotton was this town’s foundation.
This thick cloth decided the weaving history. With its indigo-dyed face and white back, the thick cloth closely resembled the work-clothes fabric from across the sea, and domestic denim is handed down as having sprung from here. At its peak in the 1970s, much of the nation’s jeans were woven in this land. Meanwhile, a highland in a mountain village to the north holds another history. This highland, 300 to 400 meters above sea level, is blessed with the darkness of its night sky; in 1989 it enacted the nation’s first rule to curb the harm of artificial light, and in 2021 it was recognized as the country’s third area to protect the starry sky. The path to becoming a city mirrors this town too. In the mid-Showa era four towns and seven villages became one and gained city status, and in the Heisei era two towns were absorbed to form the present municipal area. Indigo and weaving, the source of domestic denim, the dark-sky highland, and the absorption of two towns — this town’s form stands on the history of weaving and a starry sky, inscribed by the thick cloth woven with indigo and cotton.
Source: Ibara City / Ibara Denim (cotton cultivation began here in the late Sengoku period, and with indigo dyeing added in the Edo period, indigo-dyed thick cotton cloth became a local specialty, sold across the country as “Bicchu Kokura” in the Meiji and Taisho eras; the thick cloth — indigo on the face, white on the back — is said to be the origin of domestically made denim, and at its 1970s peak the area wove much of the nation’s jeans — overview) / Ibara City, Bisei Town / light-pollution control and the starry sky (on a highland 300–400 m above sea level, in November 1989 the nation’s first ordinance to prevent light pollution was enacted to protect the dark night sky, and in 2021 the area became Japan’s third certified Dark Sky reserve — overview) / Ibara City (in the southwest of Okayama Prefecture, bordering Hiroshima Prefecture to the west; municipal status in 1953 through the merger of four towns and seven villages; on 2005-3-1 it absorbed Yoshii Town of Shitsuki District and Bisei Town of Oda District — overview)
03 · In the weaving land where domestic denim arose from indigo-dyed thick cloth, absorbing two towns and losing population
What characterizes Ibara-shi is that, while carrying the history of weaving and the starry sky, it has lost population after absorbing two towns. Within the post-absorption area, from 45,104 in 2005 to 38,384 in 2020, nearly seven thousand were lost over fifteen years. Even in a town that wove much of the nation’s jeans, the aging of the weaving workforce overlapped with some of the younger generation moving toward larger cities, and the whole town’s age can be read as having risen. That the share aged 65 and over neared four in ten at 37.4% in 2020 is the sign of that. In particular, in the mountain-village districts added by absorption, the population is thought to be falling faster than in the city center.
Meanwhile the Childcare Waitlist was zero in both 2024 and 2025, households with children make up 18.6% (2020), and the crude birth rate was 5.0 per thousand in 2020. A Fiscal Capacity Index of 0.39 is a level whose own tax revenue covers only about four-tenths of expenditure. Rather than tracing the table of indicators, what I want to follow is the path by which the native craft of weaving indigo-dyed thick cloth was reread as a substitute for the work-clothes fabric from across the sea and grew into the weaving cluster called the source of domestic denim. This chain — rereading a native craft for another use — does not ride on figures like fiscal capacity 0.39 or a falling population.
Source: Population Census (Statistics Bureau, MIC) / Local Government Finance Survey, Fiscal Capacity Index (MIC) / Childcare Facility Status Report (Children and Families Agency)
04 · A land that weaves with indigo and cotton came to hold the source of domestic denim and a dark night sky
In Ibara, livelihoods of differing character have taken root. One is the history of a weaving village: from cotton growing at the end of the Sengoku period and indigo dyeing in the Edo period it produced indigo-dyed thick cotton cloth, and that thick cloth is held to be the source of domestic denim. Another is its character as a land of the starry sky, holding on a northern mountain-village highland the nation’s first rule to curb the harm of artificial light, guarding a dark night sky. And it has the face of a merger journey: four towns and seven villages became one city, and in the Heisei era two towns were absorbed. A village that weaves indigo-dyed thick cloth gave rise to the source of domestic denim, and the northern mountain highland has guarded a dark night sky.
To weave cloth with eye and hand close upon it, and to guard the dark by deliberately holding back light. Through both runs the same stance — not letting go of, but guarding, what is hard to see. The individuality of the town of Ibara lies precisely there: that these two livelihoods coexist within a single municipal area.
Source: Ibara City / Ibara Denim (cotton cultivation began here in the late Sengoku period, and with indigo dyeing added in the Edo period, indigo-dyed thick cotton cloth became a local specialty, sold across the country as “Bicchu Kokura” in the Meiji and Taisho eras; the thick cloth — indigo on the face, white on the back — is said to be the origin of domestically made denim, and at its 1970s peak the area wove much of the nation’s jeans — overview) / Ibara City, Bisei Town / light-pollution control and the starry sky (on a highland 300–400 m above sea level, in November 1989 the nation’s first ordinance to prevent light pollution was enacted to protect the dark night sky, and in 2021 the area became Japan’s third certified Dark Sky reserve — overview) / Ibara City (in the southwest of Okayama Prefecture, bordering Hiroshima Prefecture to the west; municipal status in 1953 through the merger of four towns and seven villages; on 2005-3-1 it absorbed Yoshii Town of Shitsuki District and Bisei Town of Oda District — overview)
05 · Atlas note — reading the same stance of guarding what is hard to see
Lay out Ibara’s numbers and the indicators of a weaving town raising its age line up: a population that falls after absorption, an aging rate of 37.4%, a household-with-children share of 18.6%, fiscal capacity of 0.39. But rather than trace the table of indicators, what I (Atlas) want to follow is the path by which a weaving cluster called the source of domestic denim rose up from the craft of weaving indigo-dyed thick cloth. That the indigo-dyed thick cloth resembled the work-clothes fabric from across the sea is what turned this land toward becoming the source of domestic denim. The chain by which a native indigo-dyeing craft was reread as a substitute for imported fabric and remained as a weaving cluster shows a thickness that does not appear in this town’s figures.
One more thing to weigh is that this town is “a weaving village and, at the same time, holds a highland that guards a dark night sky.” In the choice to deliberately hold back light, a sense that finds value in what is hard to see is at work. The craft of weaving, checking the weave of the cloth by hand, and the work of deliberately guarding the darkness of the night sky. Through these two, which seem at first unrelated, runs the same stance — not letting go of, but guarding, what is hard to see. The indigo-dyeing hand, and the night with its light turned down — what no amount of gazing at Ibara’s numbers will yield is that same stance, repeated twice over within this single city.
Source: Population Census (Statistics Bureau, MIC) / Ibara City / Ibara Denim (cotton cultivation began here in the late Sengoku period, and with indigo dyeing added in the Edo period, indigo-dyed thick cotton cloth became a local specialty, sold across the country as “Bicchu Kokura” in the Meiji and Taisho eras; the thick cloth — indigo on the face, white on the back — is said to be the origin of domestically made denim, and at its 1970s peak the area wove much of the nation’s jeans — overview) / Ibara City, Bisei Town / light-pollution control and the starry sky (on a highland 300–400 m above sea level, in November 1989 the nation’s first ordinance to prevent light pollution was enacted to protect the dark night sky, and in 2021 the area became Japan’s third certified Dark Sky reserve — overview) / Ibara City (in the southwest of Okayama Prefecture, bordering Hiroshima Prefecture to the west; municipal status in 1953 through the merger of four towns and seven villages; on 2005-3-1 it absorbed Yoshii Town of Shitsuki District and Bisei Town of Oda District — 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_