A Data Analysis of the 744 'At-Risk' Municipalities — The Structure That Tokyo Siphons

On April 24, 2024, the private advisory body Population Strategy Council (chaired by Akio Mimura) classified 744 of Japan's 1,729 municipalities (43.3%) as "at-risk of disappearance."[1] The definition: municipalities in which the population of women aged 20–39 will halve between 2020 and 2050 (cf. Population Strategy Council).

What the comparison with the previous report shows

A key point of comparison is with the previous report. The 2014 "Masuda Report" (Japan Policy Council) classified 896 municipalities as at-risk; by 2024 that number had fallen to 744, with 239 municipalities escaping the designation.[2] This shift is interpretable either as evidence that countermeasures worked, or as a sign that young female out-migration accelerated and completed earlier than projected.

The severity in Tohoku and Hokkaido

Regionally, the burden falls on Tohoku and Hokkaido. The six Tohoku prefectures account for 165 at-risk municipalities — the highest of any block in both count and share — and Hokkaido for 117.[3] Together that is 282, or 38% of the national total of 744.

The two blocks hold 179 municipalities in Hokkaido and 215 in Tohoku[4]. With 282 of those 394 at risk, more than seven in ten carry the designation — against a national average of 43%.

The steepest projected decline in the two blocks is Sotogahama, Aomori: 240 women aged 20–39 in 2020, projected to fall to 30 by 2050 — a decline of 87.5%[5]. The steepest decline nationwide is Nanmoku, Gunma, at 88.0% (50 women falling to 6)[6], so the extremes are not confined to the north. But 21 of the 50 steepest declines (42%) fall in these two blocks[7] — a region holding just 394 of 1,729 municipalities, or 23%.

The contrast with Kyushu and Okinawa

By contrast, Kyushu and Okinawa have the most "self-sustaining" municipalities — those in which young women will remain at close to 50% of current levels through 2100. 34 of 65 self-sustaining municipalities (52%) are located in Kyushu and Okinawa.[8]

Why Young Women Leave and Don't Return

Across differences in industry and geography, the structural common denominator among at-risk municipalities is: "young women leave for school or work and never return."

They leave for study and do not return

Young women who move to cities for high school or university spend the key life milestones — employment, marriage, childbirth — in urban areas. In regions with few jobs (especially for women), weak healthcare, education, and child-care infrastructure, the incentive to return is limited. Births that could have contributed to rural statistics instead count in the destination city. The origin region loses population twice over.

The Specific Severity of Fishery and Agricultural Communities

In depopulated areas dependent on primary industries, out-migration of young women is compounded by rising male non-marriage rates. Fishing and farming — physically demanding, financially uncertain — are often unattractive employment options for young women. The pattern of "increasing numbers of older and unmarried men in rural communities" further suppresses birth numbers through lost marriage and childbearing opportunities.

The "black-hole municipality" concept defined by the Population Strategy Council captures the structural problem precisely. These are municipalities that attract large numbers of young women in-migrants but, because birth rates within their borders are low, contribute to national-level population decline. 21 of the 25 sit in Kanto, and 17 of those are in Tokyo.[3]

Tokyo's 17 break down as 16 special wards plus Aogashima Village in the Izu Islands[9]. Sixteen of Tokyo's 23 special wards carry the label; Chuo, Minato, Koto, Adachi, Katsushika, Edogawa and Chiyoda do not. Even the central wards split.

The double structure of the black-hole type

The black-hole problem is a double structure. First, it accelerates the hollowing-out of source regions by drawing in young people. Second, by maintaining conditions in which those in-migrants do not or cannot give birth, it sustains low fertility at the destination too. Tokyo concentration involves a dual problem: raising the probability of disappearance for rural areas while Tokyo itself records a birth rate of 0.99 in 2022.

Criticism of the phrase risk of disappearing

Critiques of the "disappearance" framing do exist. Nobunko has proposed the concept of "lively depopulation," arguing that small-scale communities can remain rich and viable. RIETI, reviewing 40 years of data, notes that population collapse has not occurred as rapidly as predicted.

Yet the structural seriousness of the problem does not diminish. Population concentration in Tokyo directly reduces rural birth numbers while also suppressing births at the destination. As long as this "national depopulation accelerator" function of major cities goes unaddressed, it will be difficult for the 744 at-risk municipalities to escape their classification.

Related Columns

• Tokunoshima TFR 2.25, Higashiyama 0.76 — Mapping Birth Rates Across 1,741 Municipalities（このサイトの記事）
• Generational Pension Disparities Visualized by Birth Year（このサイトの記事）

Related Guides

• Introduction to Social Impact Evaluation — A Framework for Measuring Outcomes（このサイトの記事）

References

FY2024 Local Municipality Sustainability Analysis Report — Population Strategy Council. Population Strategy Council

40% of Municipalities 'At Risk of Disappearance': Young Female Population to Halve in 30 Years — Nikkei Shimbun. Nikkei Shimbun

Re-examining At-Risk Municipalities: What Does 40 Years of Data Tell Us? — RIETI. RIETI Special Report

Creating Lively Depopulation: A Perspective Beyond the Municipal Disappearance Theory — Nobunko Editorial Team. Rural Culture Association Japan

2024 Update: What Are At-Risk Municipalities? Challenges and Recovery Cases for 744 Municipalities — TURNS Editorial Team. TURNS

Recommended Reading

地方消滅 東京一極集中が招く人口急減 (Regional Extinction — The Sharp Population Fall Brought on by Concentration in Tokyo)

増田寛也 編著

The book version of the 2014 “Masuda Report,” which first put forward the idea of municipalities at risk of disappearing.

View on AmazonPR

地方消滅の罠 「増田レポート」と人口減少社会の正体 (The Trap of Regional Extinction — The “Masuda Report” and the Reality of a Shrinking Society)

山下祐介

A counter-argument to the Masuda Report, on what regions actually look like and what they can still do.

View on AmazonPR