Field Notes

source

My Number FAQ

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The Japanese Digital Agency’s official FAQ on the My Number (Individual Number) system, covering use restrictions and number changeability. The saved snapshot is the live page, with the .raw.html companion kept as the provenance copy.

What the page establishes

Japan designed its national identifier as the negative image of Sweden’s:

  • the 12-digit number may be used only for procedures specified by law — social security, tax, and disaster response;
  • collecting or storing another person’s My Number is prohibited even with consent, outside those legal purposes, with criminal penalties;
  • agencies do not link records using the number itself but through special codes, and personal data stays decentralized across the pension offices and municipalities that hold it;
  • the Mynaportal lets the subject check the history of data exchanges between agencies;
  • and while the number is held for life and cannot be changed freely, it can be changed on the holder’s application or by the municipal mayor if there is a risk it has been or will be leaked and misused.

The agency’s own rationale explicitly cites foreign failures — US Social Security number fraud and South Korean resident-registration-number abuse — as the reason for restricting the number’s scope by law.

Limitations

The FAQ is the operator’s account of a system whose practical enforcement is not independently measured here; Japan’s tax data are not public and no people-search industry is addressed. The leak-triggered change route’s real-world availability (evidence thresholds, frequency of use) is not documented on this page.

Significance for the wiki

Japan is the locked-identifier pole of the comparison: a universal number that is legally sealed, non-commercial, non-linking, and resettable upon exposure — the last being a feature Sweden’s personnummer lacks entirely. Anchors the Japanese row of Public-by-default identity in international comparison.

Built on 1 source (1 external).

Working out connections…