Japan's My Number Card Explained: The National Digital ID Rollout and Its Controversies
My Number is Japan's national identification number system, and the My Number Card is its physical token — a smartcard with an embedded IC chip that links a resident to a unique 12-digit identifier issued by the government. The system is one of the most consequential digital-infrastructure projects in any advanced economy, and it has been politically contentious at almost every step. Understanding what the card is, what it does, and why it matters is essential background to any Japanese digital-policy story.
What My Number Is
Every resident of Japan — citizens and long-term foreign residents alike — is assigned a 12-digit My Number by the local municipality where they are registered. The number itself is permanent and cannot be changed except in cases of leakage or fraud. The card is the optional, physical instantiation of that number: a photo ID the size of a credit card, with an IC chip that holds the number and supports several digital functions.
The card enablesthree categories of service:
- Digital identity verification. When an online service needs to confirm that a person is who they say they are — opening a bank account, applying for a government service, filing taxes online — the card's chip and PIN can be used as a verified identity credential via a card reader or a smartphone with NFC support.
- Linked public-service accounts. The card carries credentials that let holders log in to online portals for taxes, social security, and health insurance, replacing the patchwork of paper certificates that previously authenticated Japanese residents.
- Digital certification and electronic signatures. The chip supports a public-key certificate for signing electronic documents, which has become more important as Japanese e-government services have expanded.
What the Card Links To
The reason the rollout is controversial is not the card itself, which is largely unremarkable by international standards, but what the underlying number connects across government systems. By design, My Number was created so that three previously separated data domains could speak to each other:
- Tax administration — income tax, local taxes, and tax deductions, including the large "my-number-style" tax deduction scheme introduced for household and personal spending.
- Social security — pensions, health insurance, unemployment insurance, long-term care, and child benefits, all of which previously required separate documentation.
- Disaster response and administrative services — proof of identity at shelters and rapid verification of resident status in emergencies.
A separate card, the Individual Number Card (which is what the My Number Card technically is), does not directly store health or tax data on its chip. But the number is the key that lets authorised agencies retrieve that data from their respective systems. For people concerned about state surveillance, that is precisely the point of contention.
Why Adoption Has Been Slow and Politically Fraught
When the My Number system was introduced in 2016, the government's goal was universal card uptake within a few years. Reality was different. Card issuance has lagged targets almost continuously, for several reasons:
- Privacy concerns. After decades in which Japan had no central citizen registry number and administrative data was siloed, many residents object to the data integration itself, regardless of the security model.
- High-profile data incidents. Several cases of personal data being leaked or mistakenly registered to the wrong individual, particularly involving the health insurance linkage, undermined public trust at critical moments.
- Mistrust of digital policy delivery. The My Number rollout is often cited alongside other digital-government missteps in Japan, including the "Digital Agency" reforms and debates over how much of the system should be run by private vendors.
- Inertia. For many older residents, the existing paper-document system was usable; a digital ID card added friction rather than removing it.
Each new benefit attached to the card — digital vaccination certificates, online tax filing, the new household tax deduction scheme — has raised uptake by a few percentage points. The government now links an increasing number of high-value services to the card specifically to drive adoption, which in turn feeds the criticism that residents are being coerced rather than persuaded.
Why It Matters
Japan's My Number is a case study in how hard it is to land a national digital identity system in an advanced democracy, even when the technical design is reasonable. The architecture is not unusual: manycountries have a citizen ID number, a chip card, and linked services. What distinguishes the My Number rollout is the combination of strong privacy culture, fragmented legacy systems, and high-profile operational errors that have made every expansion a political event.
For identity, banking, and immigration purposes the trajectory is clear: more services, more linkages, and gradually higher coverage. The remaining questions are political and operational — how data integration is governed, how incidents are handled, and whether the system can earn the trust that its designers assumed it would be granted.