9maps.com is a place where data published by national and local government is made readable on a map. Things you would never notice in a table or a PDF can be obvious at a glance on a map. We make that possible down to the level of individual municipalities.
What the movement of people shows
Population change cannot be read from a single number. Births minus deaths (natural change) and people moving in minus people moving out (migration) mean completely different things, even when both produce the same word: decline. The first takes decades to turn around; the second can reverse in a few years. Separate the two, put them on a map at municipal level, and this is what comes into view.
- A prefecture can be shrinking while some of its municipalities grow. Prefecture-level totals hide the pull of the capital city and the towns around it.
- Where people came from, and where they went. Japan’s concentration in Tokyo is real, but for many areas the larger exchange is with the neighbouring prefecture or the nearest city. The lines on the map show you the catchment a place actually belongs to.
- A rough view of the next fifteen years. A town that keeps gaining people and a town that keeps losing them are working from different assumptions about whether the shops, the schools and the bus routes will still be there.
- A way to check whether policy worked. Where a local government has pushed relocation grants or childcare support, next year’s figures show whether arrivals actually rose.
All of these figures are published free of charge by the Japanese government. But they are published as tables and PDFs, in which you cannot see where. 9maps.com puts that published material back onto a map, down to the level of individual municipalities. It is meant for people deciding where to live or relocate, people whose work touches a region, and anyone doing research or preparing material.
What we care about
- Name the source. We always state which statistic the figures come from, and for when.
- Never hide the processing. Where two statistics disagree, we say why.
What is published now
Population Flow Map (/jinko/) — population change for all 1,741 municipalities in Japan, and the movement of people between prefectures and between municipalities, shown on a map. Japanese only for now.
Work-Friendly Cafe Map (/cafe/) — cafes in Tokyo’s 23 wards and Osaka City where you can use power outlets and Wi-Fi to study or work.
Where the data comes from
The figures and the shapes in the Population Flow Map are our own processing of the following official publications.
- Statistics Bureau of Japan — Population Census (preliminary tabulation)
- Ministry of Internal Affairs and Communications — Population, Vital Statistics and Number of Households Based on the Basic Resident Register
- Ministry of Internal Affairs and Communications — Report on Internal Migration in Japan Based on the Basic Resident Register
- Ministry of Land, Infrastructure, Transport and Tourism — National Land Numerical Information (administrative boundaries)
- J-LIS — Local Government Codes of Japan
How we process them, and why two statistics do not add up to the same total, is set out in section 2 of the Terms of Use.
How often this is updated
Once a year. Every statistic behind these maps is published annually.
After the Ministry of Internal Affairs and Communications releases the Basic Resident Register population and the annual migration report, we rebuild all 1,741 municipalities. The exact reference date of every figure is stated under “Sources” on each page.
If the publisher issues a correction, or a clear error is found, we fix it without waiting for the annual update.
Operator
Iroha Production (いろは企画). Published September 2026.
The operator also writes Yutahapi Blog (yutahapi.com, in Japanese), which looks at the same question from the other side: where people live, and where they move to.
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