JAM

Data and Sources

This page summarizes the statistics and boundary data used by JAM, their reference dates, calculations, and important limitations. The reference period displayed on each visualization should also be checked.

Statistical data

Foreign residents by prefecture

This dataset is the Ministry of Justice's Statistics on Foreign Residents by prefecture and nationality or region. It is used for the Japan map, rankings, and prefecture details.

Statistics table ID
0003147229
Reference period
The reference period displayed on each page
Uses
Japan map, rankings, and prefecture details

Prefecture population for standard display

This is total population from the Statistics Bureau of Japan's Population Estimates. Standard population displays use values as of October 1, 2024.

Statistics table ID
0003448231
Reference period
October 1, 2024
Uses
Standard population display

Prefecture population used for population share

Population share is calculated from foreign resident counts from June 2017 and total population as of October 1, 2017, using different statistical tables and reference dates.

Statistics table ID
0004021108
Reference period
October 1, 2017
Uses
Population-share calculation

Municipality foreign residents and composition

This is municipality-level data from the Ministry of Justice's Statistics on Foreign Residents for June 2017. It is used for municipality maps, lists, and nationality composition.

Statistics table ID
0003147283
Reference period
June 2017
Uses
Municipality maps, lists, and composition

How display data is retrieved

JAM prefers a complete synchronized Supabase snapshot. Only when a snapshot is incomplete or a temporary communication failure occurs may the relevant data be retrieved from e-Stat as a fallback.

Nationalities supported by municipality statistics

Municipality statistics support the following classifications. A nationality may be selectable in the full nationality selector while still being unavailable in municipality statistics.

  • Total
  • South Korea
  • China
  • Taiwan
  • Vietnam
  • Philippines
  • Nepal
  • United States
  • Brazil

Boundary data

Administrative boundaries use the National Land Numerical Information Administrative Area Data (N03), provided by Japan's Ministry of Land, Infrastructure, Transport and Tourism, as of January 1, 2025. Boundary data is not the source of statistical values.

Created by JAM by processing the National Land Numerical Information Administrative Area Data provided by the Ministry of Land, Infrastructure, Transport and Tourism.

JAM converts the source data into TopoJSON for display and serves it as a static file from the same origin as JAM.

National Land Numerical Information: Administrative Area Data (opens in a new tab)

Use of the e-Stat API

Official Japanese notice

このサービスは、政府統計総合窓口(e-Stat)のAPI機能を使用していますが、サービスの内容は国によって保証されたものではありません。

English translation (provided by JAM)

This service uses the API functions of the Portal Site of Official Statistics of Japan (e-Stat), but the contents of this service are not guaranteed by the Government of Japan.

Data limitations

  • JAM does not guarantee current real-world conditions. Check the reference period displayed on each page.
  • Foreign resident and population data may have different reference dates. Population share uses June 2017 foreign resident counts and population as of October 1, 2017.
  • Municipality statistics support only some nationality classifications.
  • No data does not mean zero residents. A value may be missing from the source or unavailable in the statistical classification.
  • Municipality statistics and the 2025 boundary data use different reference dates, so names, administrative codes, and areas may not align.
  • There may be a delay between publication on e-Stat and synchronization to Supabase.
  • An e-Stat fallback may occur when synchronized data is incomplete or a temporary failure occurs.
  • Changes, suspension, or communication failures in external data services may prevent data from being displayed.
  • JAM does not control the content, accuracy, or availability of Google Maps.