DatumJapan

Methodology

How we choose, license, and verify the data — and the lines we won't cross.

Primary sources only

We publish only data from official primary sources that explicitly permit free secondary use: Japan's statistics portal e-Stat, the Statistics Bureau, the Bank of Japan, the Ministry of Finance, the Cabinet Office, Japan Customs, and the Ministry of Land, Infrastructure, Transport and Tourism. Most of these release data under Japan's Government Standard Terms of Use, which is compatible with a CC-BY licence: free to reuse with attribution.

We do not use proprietary or licence-restricted market data. In particular, we do not republish exchange data or stock indices such as TOPIX or the Nikkei 225, because their terms require a paid licence for redistribution.

Citation on every chart

Each chart names the agency that published the figure, links back to the source, states the licence, and shows the date of the latest observation and when we last updated. Where a source's terms require a specific credit line, we print it.

Verification

Before a chart is published, the latest value is checked against the figure the agency itself published on its summary page. Our data pipeline also validates each dataset automatically — checking the shape of the data, that dates are in order, that values are present, and that the citation is attached — so a malformed feed fails the build rather than reaching a chart. When we compute a figure ourselves (for example, converting units or a year-on-year change), we say so, because the source terms ask us not to present edited data as an official figure.

What we don't do

We don't give investment advice, make market calls, or set price targets. We don't use hype or clickbait. We describe what the data is and how it's measured, and we leave the interpretation to you. Data can be revised by its source after publication; recent figures (especially GDP) may change.

Current sources

  • USD/JPY — Bank of Japan
  • JGB yields — Ministry of Finance, Japan (JGB Interest Rate)
  • Policy rate — Bank of Japan
  • Money stock — Bank of Japan
  • Trade balance — Ministry of Finance, Trade Statistics of Japan (Japan Customs)
  • CPI / inflation — Statistics Bureau of Japan, via e-Stat coming soon
  • Unemployment — Statistics Bureau of Japan (Labour Force Survey), via e-Stat coming soon
  • Industrial production — Ministry of Economy, Trade and Industry (METI), Indices of Industrial Production, via e-Stat coming soon
  • Real GDP — Cabinet Office, Government of Japan (Economic and Social Research Institute), via e-Stat coming soon