The My Number Card, officially designated the Individual Number Card (個人番号カード, Kojin Bangō Kādo), is a government-issued integrated circuit identification card provided to Japanese citizens and foreign residents, embedding a unique 12-digit "My Number" for streamlining administrative processes in taxation, social security benefits, and disaster response.[1] It incorporates a photograph, personal identifiers such as name, address, date of birth, and gender, alongside an IC chip that supports electronic public key certificates for secure digital authentication and identity verification in both public and private sectors.[2] Launched in January 2016 under the My Number System established by the 2013 Social Security and Tax Number Law, the card facilitates convenient access to government services, including online applications and integration with health insurance since its phased implementation beginning in 2021.[3]By October 2024, over 100 million cards had been issued, reflecting issuance rates exceeding 80% of the eligible population amid government incentives like administrative fee reductions, though voluntary participation has varied due to technical implementation challenges.[4] The system's push toward digital transformation, including mandatory linkage to health insurance cards by December 2024, has encountered persistent hurdles such as software glitches in name matching—exacerbated by Japan's complex kanji variations—leading to erroneous denials of service and heightened public distrust.[5][6]Health insurance utilization rates lingered at approximately 30% through mid-2025, with reports of widespread errors prompting card returns and calls for system overhauls, underscoring causal failures in software reliability and data integration over initial privacy apprehensions.[5][7] Incidents of forged cards and unauthorized access have further eroded confidence, despite security features like biometric-linked smartphone variants piloted in 2025.[8][9]
History
Background and Predecessors
Prior to the introduction of the My Number system, Japan's administrative processes for taxation, social security, and resident services relied on decentralized, paper-intensive systems centered around the koseki family registry and municipal resident registers. These frameworks, rooted in post-World War II reforms, required manual cross-verification across local governments and agencies, resulting in duplicated efforts, verification delays, and errors in eligibility assessments for benefits such as pensions and tax filings.[10][11]In response to these inefficiencies, the government launched the Basic Resident Registers Network (Juki-net) in August 2002, linking municipal resident registers to facilitate nationwide sharing of core demographic data including names, addresses, birth dates, and gender. Juki-net aimed to streamline local administrative tasks like address changes but was constrained by its narrow scope—limited to basic residency information without integration into taxation or social security databases—and required voluntary opt-in for an 11-digit Juki card, leading to low adoption rates amid privacy lawsuits challenging its constitutionality.[12][13][10]Demographic shifts exacerbated these limitations, as Japan's population aged rapidly—with those aged 65 and older comprising 23% by 2010—necessitating more efficient mechanisms for distributing social security benefits and reducing administrative redundancies in eligibility checks. The 2011 Tōhoku earthquake and tsunami further exposed vulnerabilities in siloed data systems, where fragmented records across ministries hindered timely victim identification, aid distribution, and inter-agency coordination during the crisis that claimed over 15,800 lives.[14][15][16]
Legislative Establishment
The Act on the Use of Numbers to Identify a Specific Individual in Administrative Procedures (Act No. 27 of 2013), commonly referred to as the My Number Act or Number Act, was promulgated on May 31, 2013, and established the legal foundation for Japan's individual numbering system.[17] This legislation mandated the assignment of a unique 12-digit Individual Number—known as "My Number"—to every resident, including Japanese nationals and foreign residents with valid residency status, to serve as a common identifier across government administrative functions.[18] The Act specified its primary applications in taxation, social security benefits, and disaster response measures, aiming to consolidate disparate identification processes that previously relied on multiple, non-unified resident registration systems.[18]At its core, the law sought to rectify administrative redundancies inherent in siloed government databases, where overlapping data collection for taxes, welfare, and pensions led to inefficiencies, errors, and higher operational costs amid Japan's demographic challenges, including a shrinking workforce and rising social expenditures.[19] By enabling secure, targeted information linkage without centralized storage of all personal data, the framework promoted verification accuracy and resource allocation, drawing on principles of streamlined causal chains in public administration to minimize duplication and support fiscal sustainability.[20] The Act included provisions for enhanced personal information safeguards, such as restrictions on number usage beyond designated purposes and penalties for unauthorized disclosure, to balance utility with privacy constraints under Japan's existing dataprotection statutes.[18]Implementation proceeded in phases to facilitate preparation: assignment notifications for My Numbers were distributed to households starting in October 2015, marking the operational commencement of number allocation.[21] Full enforcement for administrative procedures began January 1, 2016, coinciding with the voluntary issuance of the My Number Card, an optional IC-embedded document displaying the holder's number, name, address, date of birth, and gender for authentication in eligible transactions.[22][23] This staggered rollout allowed agencies to integrate systems while limiting initial mandates to number notification rather than universal card adoption.[19]
Initial Rollout and Early Adoption
The Individual Number Card, commonly known as the My Number Card, began issuance to the public in January 2016, following the assignment of 12-digit individual numbers to all residents since late 2015. The card features an integrated IC chip for electronic authentication and certificate functions, alongside a photograph, enabling its use as an official photo ID for identity verification in administrative procedures.[24][23]To encourage adoption, the government promoted early benefits such as streamlined online tax filing through the e-Tax system, where cardholders could bypass certain paperwork and expedite deductions for medical expenses or other claims. Additional conveniences included easier access to resident certificates via convenience stores and integration with select local government services. Despite these incentives, uptake remained low; by early 2020, only about 16% of the eligible population—roughly 20.33 million cards—had been issued, reflecting limited public familiarity and reluctance amid concerns over data security and mandatory notifications.[25][26][27]The COVID-19 pandemic from 2020 highlighted both the card's potential for contactless verification in emergency aid distributions, such as online applications for universal cash payments, and persistent execution gaps in Japan's administrative digitization. The government responded with the My NaPoint program, launched in September 2020, offering up to 20,000 yen in points for new applicants to boost issuance rates, yet initial hurdles in public trust and infrastructure readiness underscored the challenges of transitioning from paper-based systems.[27][28]
Legal and Administrative Framework
Key Legislation
The Act on the Use of Numbers to Identify a Specific Individual in Administrative Procedures (commonly known as the My Number Act), promulgated on May 31, 2013, as Act No. 47 of 2013, establishes the legal foundation for Japan's individual identification number system.[29] This legislation assigns a unique 12-digit number, termed the "individual number" or My Number, to every resident, including Japanese nationals and foreign residents, for streamlining administrative processes while imposing strict limits on its application.[30] Core provisions confine the number's use primarily to three domains: social security (encompassing pensions, welfare, and health insurance eligibility), taxation (for income reporting and deductions), and disaster response (facilitating aid distribution and victim identification).[29]Article 19 explicitly prohibits the collection, storage, or provision of "specific personal information" (data linked to My Number, such as income or medical records) beyond these specified purposes, with violations subject to penalties including fines up to 1 million yen or imprisonment for up to one year.[20]Subsequent amendments have expanded integration while reinforcing safeguards. The Act was partially amended in 2021 to promote My Number linkage with health insurance systems, enabling electronic verification of eligibility and reducing administrative duplication.[31] Further revisions under Law No. 48 of 2023 mandated the abolition of standalone paper health insurance cards, with issuance ceasing on December 2, 2024, and full phase-out by the end of 2024, requiring reliance on My Number Cards or digital alternatives for medical claims processing.[30] These changes aim to centralize data flows for efficiency but maintain voluntary issuance of the physical My Number Card, though non-issuance increasingly imposes practical barriers to services like tax refunds or insurance reimbursements, creating de facto incentives for adoption.[31] Enforcement relies on the Personal Information Protection Commission for oversight, with misuse penalties escalated in amendments to deter unauthorized data handling by public or private entities.[20]
Scope of Application and Mandates
The My Number system, established under the Act on the Use of Numbers to Identify a Specific Individual in Administrative Procedures (commonly known as the My Number Act), limits the use of individual numbers to streamlining administrative procedures in specified fields, including social security, taxation, and disaster countermeasures.[30][29] These numbers facilitate information sharing among government agencies for purposes such as verifying eligibility for benefits, processing tax returns, and coordinating relief efforts, but the Act explicitly prohibits their application to unrelated data aggregation or surveillance activities outside these domains.[30][29]Article 19 of the Act delineates authorized entities, such as administrative organs and local governments, that may handle numbers for these procedures, while Article 20 forbids any person from collecting or retaining specific personal information containing My Numbers except in statutorily permitted cases, such as tax withholding or social insurance reporting.[29]Businesses and employers face mandates to collect My Numbers from employees, contractors, and payees for income tax withholding and submission of payment records to tax authorities, effective since the system's implementation in 2016.[32][33] Failure to obtain and report these numbers can result in penalties under tax laws, as they are required for accurate withholding tax procedures on salaries, dividends, and other payments.[34] However, the My Number Card itself remains voluntary for residents, with issuance upon application but no legal obligation to possess one; non-holders may still provide their number via notification cards for required procedures, though some services may deny access or impose inconveniences without the card's authentication features.[35][36]Recent legislative expansions have integrated the My Number Card with health insurance functions, abolishing paper health insurance cards as of December 2, 2024, to enable electronic verification of insured status at medical facilities.[37][38] This shift mandates use of the card (or qualified alternatives for those without) for accessing healthcare services, aiming to reduce administrative errors and enable data sharing for treatment continuity, while the government targets further authentication expansions, such as potential linkage with residence cards, by 2025 to enhance overall system utility.[37][39]
Technical Design
Card Specifications
The My Number Card is constructed as a durable plastic integrated circuit (IC) card compliant with international standards for contactless smart cards, featuring laser-engraved text and intricate color patterns to enhance resistance to counterfeiting and wear.[2] The front side displays the holder's photograph, name, address, date of birth, and sex, while the reverse includes the 12-digit individual number.[24] The card's embedded IC chip utilizes near-field communication (NFC) technology for non-contact reading by compatible devices, enabling secure data exchange without physical insertion.[40]The IC chip stores electronic certificates for public key infrastructure authentication, including those for digital signatures and user identification, alongside minimal personal details such as the holder's name, address, date of birth, and gender.[2] It does not retain highly sensitive information like tax or pension records, with data maintained locally on the chip rather than in a centralized repository linking all attributes.[2] Access to chip contents requires a 4-digit personal identification number (PIN), which locks after repeated incorrect entries; optional biometric variants employ facial recognition in lieu of a PIN for authentication, storing reference facial data for verification against the holder's photo.[40][36]Engineered for a 10-year validity period matching the card's physical lifespan, the design incorporates robust materials to withstand everyday handling, though the internal IC chip and antenna demand careful treatment to prevent malfunction from bending, moisture, or extreme temperatures.[41][42] In cases of loss, damage, or expiration without timely renewal, replacement involves suspending the card via a national hotline, filing a police report if stolen, and applying for reissue at a municipal office, with users incurring fees typically totaling 1,000 yen (800 yen for the card plus 200 yen for electronic certificates if requested).[40][43][44]
Security Mechanisms
The My Number Card incorporates an integrated circuit (IC) chip designed with tamper-resistant features to prevent unauthorized physical or logical access, adhering to international security evaluation standards such as those from the Common Criteria framework.[45] The chip stores electronic certificates for public personal authentication, card information verification, and resident registry network applications, but does not retain high-privacy data like financial or medical details, limiting potential exposure in case of compromise.[46] Access to chip data requires a four-digit PIN or facial authentication, with multiple incorrect attempts triggering a lockout that necessitates an in-person procedure for reset, thereby mitigating brute-force attacks.[47]Data transmission involving the card employs public key infrastructure (PKI) with electronic certificates and encryption protocols, ensuring secure online authentication compliant with Japan's Act on the Protection of Personal Information.[48] Distinct PINs are assigned to each certificate and application function, compartmentalizing access to reduce the risk of widespread misuse even if one credential is compromised.[49] In the event of loss or theft, cardholders can suspend functionality via a 24/7 hotline or mobile app, with resumption typically within one week following verification, providing a rapid response mechanism against immediate exploitation.[40]While the system logs administrative access for oversight by government agencies, it does not enable real-time tracking of individual cardholder activities, balancing security with privacy constraints under statutory mandates.[47] These mechanisms collectively address tampering risks by relying on hardware isolation, cryptographic protections, and procedural controls rather than centralized monitoring, though their efficacy depends on user adherence to PIN management and prompt reporting of incidents.[48]
Features and Uses
Core Government Applications
The My Number Card facilitates electronic tax filing through the e-Tax system, allowing users to submit final tax returns online with automatic population of required data such as tax deduction certificates from linked government records, thereby eliminating the need for manual document submission.[50] This integration verifies the holder's identity via the card's electronic certificate, streamlining the process compared to paper-based returns that require physical proof of My Number and attachments like income certificates.[25] Post-implementation, such applications have reduced attached documentation requirements, such as omitting tax certification proofs, which previously necessitated separate requests and verifications.[51]In social security administration, the card enables claims for benefits like child allowances without repeated paperwork, as pre-linked data across agencies allows for automated eligibility checks and direct processing via the Mynaportal platform.[50] For pension services, holders can apply online for National Pension premium exemptions or postponements and access contribution records, bypassing in-person visits and manual identity confirmations that demand multiple documents.[50] These uses leverage the card's role as an official photo ID, confirming both My Number and personal identity in a single step, which cuts administrative collation and transcription efforts across agencies.[25][52]For disaster aid distribution, pre-registration of bank account details with the My Number system permits faster benefit transfers without additional verification documents, enhancing response efficiency by relying on centralized, confirmed recipient data.[50] This addresses limitations observed in pre-2011 events like the Tōhoku disaster, where fragmented records delayed aid; the system's design post-2013 rollout supports quicker identity and eligibility matching in emergencies, reducing processing burdens on local governments.[27] Overall, these applications contribute to administrative efficiency by minimizing redundant data entry and inter-agency coordination time, though specific quantitative reductions in processing durations vary by procedure and adoption rate.[53]
Integration with Health Insurance
The integration of the My Number Card with Japan's health insurance system began with legislative revisions enabling the use of the card as a substitute for traditional health insurance cards, culminating in the cessation of new paper card issuance on December 2, 2024.[38][39] This shift ties patient information directly to the 12-digit My Number identifier, allowing medical institutions and pharmacies to verify eligibility electronically via the card's IC chip during visits.[54] Existing paper cards remain valid until their expiration or until holders transition, but the policy aims for full reliance on digital verification to streamline administrative processes.[55]Under the integrated system, patients present the My Number Card at healthcare facilities, where providers generate "qualified medical invoices" linked to the individual's number for record-keeping and reimbursement claims.[56] This linkage facilitates the creation of a centralized electronic medical record database, enabling interoperability across insurers and providers to track treatment histories and prevent redundant procedures such as duplicate vaccinations or tests.[50] For instance, the system supports online submission of claims by insurers to the government, reducing paperwork and accelerating payouts, with initial pilots demonstrating potential efficiency gains in data matching.[57]To address privacy concerns, the integration includes opt-out mechanisms, such as requesting paper-based notifications for medical expense receipts instead of electronic sharing, allowing individuals to limit data linkage to specific encounters.[58] However, full utilization requires patientconsent for data sharing, and non-My Number holders can still access services via alternative verification methods provided by insurers.[39]Despite these features, adoption at medical institutions has been limited, with usage rates hovering between 15% and 30% as of mid-2025, attributed to incomplete system readiness among smaller clinics and pharmacies lacking compatible readers or staff training.[5][59] A March 2025 public opinion survey indicated that 45.8% of respondents had begun using the My Number Card for insurance purposes, though institutional verification rates lagged due to phased rollout dependencies.[60][61]
Expansion to Private Sector and Other Services
The Japanese government, through the Digital Agency, has actively promoted the integration of My Number Cards into private sector operations via initiatives such as the "Friends of My Number Card Association," which supports businesses and local governments in expanding card usage beyond public services.[62] This includes guidelines for leveraging the card's public personal authentication service (JPKI) for online identity verification, with over 580 companies adopting it for eKYC processes as of August 2024.[63] Such expansions are largely market-driven, as private entities voluntarily integrate the card to streamline customer onboarding and reduce fraud, though government incentives like usage points have accelerated adoption.[64]In financial services, My Number Cards facilitate bank account linkages, enabling seamless verification for account openings and transfers, with financial institutions required to collect individual numbers under the Deposit Account Number System for compliance and operational efficiency.[30] By late 2024, the My Number Portal API supported 197 private business services, including payment processing and authentication, contributing to broader private adoption amid government pushes for API expansions in fiscal 2024.[65] Pilots for mobile authentication have extended to utility and telecom sectors, where cards integrated with smartphone apps allow secure logins and bill payments, though uptake remains pilot-stage rather than widespread.[66]From spring 2025, further private sector expansions are planned, including deeper digital wallet integrations like adding cards to Apple Wallet for in-app and point-of-sale verifications, aiming to capitalize on the card's penetration exceeding 100 million issued units by October 2024.[67][68] These developments reflect a hybrid model of voluntary private innovation guided by Digital Agency directives, with incentives such as points programs tied to private transactions boosting overall usage rates.[62]
Adoption and Implementation
Issuance and Penetration Rates
The My Number Card issuance commenced in January 2016 on a voluntary basis for eligible Japanese residents aged 14 and older. By the end of 2023, cumulative deliveries approached 90 million cards, corresponding to roughly 70% penetration among the eligible population of approximately 125 million.[69] This marked a significant acceleration from earlier years, driven by expanded administrative integrations despite initial slow uptake.In 2024, issuance momentum continued, with cumulative deliveries surpassing 100 million by August.[4] Possession rates, accounting for invalidations and deaths, reached 94.49 million cards by the end of October 2024, equating to 75.7% of the eligible population.[70] By August 2025, possession had risen to 98.84 million cards, achieving a 79.4% rate against the updated eligible base.[71]Demographic patterns show higher penetration among younger cohorts; for instance, 78.5% of 17- to 19-year-olds held cards as of mid-2023, compared to lower rates among seniors.[72] Urban areas generally exhibit stronger adoption than rural ones, though precise breakdowns vary by prefecture per Ministry of Internal Affairs and Communications data. To boost voluntary participation, the government offered incentives in 2023, including up to 20,000 yen in transferable points for card acquisition and service linkages like health insurance integration.[73] While formally opt-in, the card's role in mandatory-linked processes—such as tax filings and social benefits—has rendered it de facto essential for full civic engagement.[74]
Usage Statistics and Incentives
As of August 2025, the usage rate of My Number Cards as health insurance cards remained low at approximately 30%, even after the full integration of health insurance functionality into the cards began in December 2024.[5] This figure reflects persistent underutilization at medical institutions and pharmacies, where online eligibility verification via card readers has not achieved widespread adoption despite mandatory transition efforts.[5] In contrast, usage for tax-related purposes, such as e-filing through the e-Tax system, has been notably higher, with the card serving as a primary tool for identity verification and document submission in over 70% of electronic tax declarations by mid-2023, driven by its integration as the core identifier for fiscal administration.[50]Government incentives, particularly the MyNa Points program offering up to 5,000 yen in digital points for card applications and related services, significantly boosted issuance rates. Prior to the program's 2021 launch, penetration stood at around 15.5% nationwide as of March 2020, but applications surged, reaching 76.8% of eligible residents by June 2023, coinciding with point redemption deadlines.[4][75] These rewards demonstrably accelerated acquisition among demographics with lower prior resistance, such as younger adults, though empirical evidence indicates limited translation to sustained active usage beyond initial compliance.Regional variations in uptake highlight disparities in implementation and local engagement. For health insurance card usage as of October 2024 (the most recent detailed prefectural data available), the national average was 15.67%, but rates ranged from a high of 23.59% in Toyama Prefecture to lower figures in urban areas like Tokyo, attributed to differences in medical facility readiness and public familiarity with card readers.[59][76] Prefectures in the Hokuriku region, including Shimane, Fukui, Ishikawa, and Niigata, showed elevated rates above 20%, correlating with proactive local government campaigns but underscoring that incentives alone do not uniformly drive utilization across Japan's diverse administrative landscape.[59]
Operational Challenges
The My Number Card system's integration with existing databases has been hampered by discrepancies in name formatting, especially kanji variations for phonetically identical Japanese names, which disrupt automated matching and verification processes.[6] These issues arise from legacy resident registration systems that lack standardized encoding, leading to mismatches during data linkage for administrative services.[77]Delays in synchronizing the card with local government infrastructures have compounded these challenges, as municipalities vary in their digital readiness and procedural adherence. For example, surveys indicated that around 20% of local governments applied incorrect protocols when associating My Number data with disability welfare records, reflecting uneven implementation across Japan's decentralized administrative framework.[78] In the lead-up to the December 2024 health insurance merger, 41% of municipal heads requested a postponement, citing inadequate system compatibility and preparation timelines tied to outdated local IT setups.[79]Resource constraints peaked during the 2023-2024 preparations for consolidating health insurance functions into the My Number Card, straining municipal IT support and personnel amid accelerated digitization mandates.[77] This rush exacerbated bottlenecks in data processing and service delivery, as local entities grappled with surging verification demands without proportional upgrades to legacy platforms.[80]Insufficient orientation for municipal staff and end-users has further impeded effective deployment, fostering operational inefficiencies and suboptimal usage rates despite policy incentives.[5] Reports highlight persistent hurdles in card activation and service access, attributable to gaps in procedural training that hinder seamless adoption at the grassroots level.[59]
Controversies and Criticisms
Data Errors and System Glitches
In May 2023, Japan's Digital Agency revealed that approximately 7,300 health insurance entries had been erroneously linked to incorrect My Number Cards, primarily due to mistakes by health insurance associations during the registration process for integrating cards with insurance data.[81] These mismatches allowed users to access unrelated individuals' medical information, stemming from input errors such as confusing names with identical pronunciations but different kanji characters, a common issue in Japanese data handling.[82] The government responded by instructing insurers to review and correct the linkages, though the incidents underscored flaws in the decentralized data integration between local governments and insurers.[83]Subsequent audits expanded the scope, with a December 2024 review of 160 million data points identifying 9,223 confirmed inaccuracies in personal information tied to My Number Cards, including persistent health data discrepancies.[84] Officials attributed many errors to procedural lapses by local municipalities and insurers, such as improper verification during initial card issuance or updates, leading to apologies from ministers and promises of manual re-verification protocols.[78] Despite these fixes, similar mismatches recurred, highlighting systemic integration challenges in linking siloed databases without robust automated cross-checks.[6]System glitches have also plagued authentication processes, particularly during peak usage periods like tax filing seasons, where high traffic volumes caused server overloads and failed logins for e-Tax submissions via My Number verification.[85] In July 2023, widespread complaints emerged about card readers and online portals rejecting valid authentications due to software incompatibilities and backend synchronization delays, prompting the Digital Agency to order comprehensive data rechecks and temporary workarounds like paper-based alternatives.[6] These recurring technical failures, often tied to inadequate scalability in the platform's architecture, have delayed administrative processes and eroded operational reliability, even as patches were deployed.[86]
Public Distrust and Opposition
Public opposition to the My Number Card has persisted since its rollout, with surveys consistently revealing majority dissatisfaction linked to perceptions of governmental mismanagement. A June 2023 Mainichi Shimbun poll found 57% of respondents opposed integrating conventional health insurance cards into the My Number system, reflecting broader skepticism toward mandatory expansions.[21] Similarly, an August 2023 Mainichi survey indicated 66% favored scrapping or postponing the health insurance merger, underscoring resistance to coercive adoption amid repeated administrative shortcomings.[87]This distrust traces to a prevailing view of bureaucratic incompetence, as mishandled implementations eroded confidence in the system's reliability and the state's capacity to execute large-scale digital reforms without disruption. Cabinet approval ratings for Prime Minister Fumio Kishida fell to 35% in a July 2023 Yomiuri Shimbun poll, with analysts attributing the decline directly to My Number-related controversies rather than isolated policy disputes.[88] Public sentiment, as captured in earlier studies, reveals that low voluntary uptake—around 30% by 2020—stems from generalized wariness of government initiatives perceived as overreaching or poorly planned, echoing failures in prior digitization efforts like regional resident registries.[89]Opposition groups and citizens have mobilized against mandates, advocating for preserved opt-out provisions and voluntary participation to mitigate risks of forced integration. Petitions and media critiques, including from opposition parties, highlighted the abrupt 2022 announcement to phase out paper health cards by late 2024 as emblematic of top-down policymaking indifferent to public apprehensions.[90] Proponents counter that such resistance hampers essential modernization, arguing the card's framework is indispensable for streamlining welfare and tax administration amid Japan's acute demographic strains, including a projected population decline to 87 million by 2070 and a shrinking labor force necessitating efficient resource allocation.[91] Despite incentives like point rebates up to ¥20,000 for cardholders, these structural imperatives have failed to fully sway skeptics wary of unproven scalability.[92]
Privacy and Security Concerns
Protective Measures and Protocols
The My Number system adheres to the Act on the Protection of Personal Information (APPI) and the My Number Act, which mandate strict handling of specified personal information, including prohibitions on unauthorized collection, use, or disclosure of individual numbers.[30] Data is not stored in a centralized mega-database; instead, personal information remains managed by respective government agencies (e.g., tax offices for fiscal data), with access limited to encrypted, need-based queries by authorized entities using the individual number as an identifier.[93] This decentralized architecture causally reduces breach risks by avoiding a single point of failure, as agencies exchange only hashed or encoded identifiers rather than full datasets, ensuring that knowledge of a My Number alone does not enable misuse of linked records.[40]Cardholders exercise direct controls over their My Number Cards, including 24/7 temporary suspension via a dedicated toll-free line (0120-95-0178) in cases of loss or theft, with resumption possible after verification and re-issuance typically within one week upon application at a municipality, incurring a fee of 1,800–2,000 yen.[40] Access to the card's IC chip requires a user-set 4-digit PIN combined with facial biometric recognition, which locks after multiple incorrect attempts to prevent brute-force attacks; PIN resets are available through municipal offices.[40] The IC chip stores only minimal data—such as the holder's photo, name, address, and number—excluding sensitive details like tax or medical records, and incorporates tamper-detection mechanisms that render it inoperable if illegally accessed.[40]The system is certified to the ISO/IEC 15408 international security standard for evaluated assurance levels, incorporating anti-forgery features like color-shifting ink and laser-etched elements on the physical card.[40] Oversight falls under the Digital Agency, which enforces protocols for secure data exchange and conducts internal risk assessments, supplemented by supervision from the Personal Information Protection Commission (PPC) to ensure compliance and prevent leaks through employee training and access logging.[19] These measures collectively prioritize layered defenses—physical, biometric, and procedural—to mitigate unauthorized access, though their efficacy depends on user vigilance and agency adherence, as decentralized queries still require robust encryption to counter interception risks.[40]
Reported Incidents and Risks
In May 2023, Japan's Ministry of Health, Labour and Welfare disclosed that between October 2021 and November 2022, 7,321 My Number cards were erroneously linked to incorrect health insurance data belonging to other individuals, highlighting systemic vulnerabilities in data integration processes.[82] This incident, stemming from administrative errors rather than external hacks, prompted widespread public complaints and an emergency government review ordered by Prime MinisterFumio Kishida in June 2023 to address glitches and potential leaks.[94]Additional errors emerged in 2023 involving mismatched bank accounts for public fund payments under the My Number system, including 748 cases of entirely unrelated individuals' accounts being registered and over 130,000 instances of family-name discrepancies, further eroding trust without evidence of intentional exploitation.[95]Forgery risks also surfaced, as demonstrated by a reported case where a counterfeit My Number card was used to hijack a resident's smartphone for unauthorized purchases totaling 2.25 million yen, underscoring physical and digital authentication weaknesses amid rising system adoption.[8]While no large-scale cyber breaches of the centralized My Number database have been publicly confirmed, the surge in related personal data leaks—from 334 to 2,052 incidents in fiscal year 2023—reflects heightened exposure risks from expanded usage across government services, potentially amplifying opportunities for hypothetical misuse in unauthorized surveillance or profiling despite statutory prohibitions on such applications.[96] These contained issues, often mitigated through suspensions and audits, illustrate trade-offs where error-prone centralization enables efficiency but invites incremental risks, with overall personal data violations reaching a record 13,279 cases in the same period.[97]
Impact and Evaluation
Efficiency and Benefits
The My Number Card enables reductions in paperwork for tax and social security procedures by supporting online submissions through platforms like e-Tax, where users can automatically retrieve and input documents such as income certificates and deduction proofs without manual collection or physical submission to offices.[50] This streamlines processes that previously required multiple in-person visits or mailed forms, shortening overall handling times for both individuals and administrators.[98] Similarly, in social security applications, the card links personal data across agencies, facilitating efficient verification and reducing redundant documentation requests.[99]In disaster response, implemented since January 2016, the system aids faster identification of victims and evacuees, allowing authorities to cross-reference My Numbers with resident records for targeted aid distribution and reducing delays in support compared to pre-system manual matching.[74] During emergencies, cardholders benefit from integrated health functions that enable medical providers to access insurance details without upfront payments or extensive explanations, particularly for unconscious patients, thereby expediting care initiation.[100]The integration of My Number with health insurance, advancing since 2021, reduces billing errors by enabling real-time datasharing among providers and insurers, which cuts administrative costs associated with claim discrepancies and manual corrections.[101] During the COVID-19 pandemic in the 2020s, the card supported efficient online identity verification for public services and vaccine-related processes, overcoming fragmentation in prior paper-based systems and enabling quicker access to benefits without repeated in-person confirmations.[102] These mechanisms demonstrate causal efficiency gains by centralizing data flows, minimizing duplication inherent in Japan's pre-2016 siloed administrative frameworks.[27]
Overall Effectiveness and Future Prospects
The My Number Card system has achieved substantial issuance rates, exceeding 100 million cards by late 2024, representing approximately 80% of eligible residents, driven primarily by government incentives such as points programs and mandatory linkages for services like health insurance.[4][5] However, active usage remains limited, with integration into daily administrative tasks hovering below 30% for key applications like health insurance verification, indicating that possession does not equate to practical adoption and highlighting gaps in perceived utility or trust.[5] This disparity underscores a mixed effectiveness: while the system streamlines data matching in targeted government processes, reducing administrative redundancies where utilized, persistent low engagement rates suggest incomplete realization of efficiency gains, as voluntary participation lags behind coerced issuance.[80]Evaluations from official dashboards and policy reviews portray the system neither as a comprehensive surveillance mechanism nor an outright failure, but as a pragmatic administrative tool hampered by implementation flaws like data mismatches and public skepticism, which have eroded confidence without delivering proportional benefits in cross-agency coordination.[103][104] Empirical evidence from usage metrics refutes hyperbolic claims of total inefficacy, as evidenced by incremental improvements in linked services, yet causal analysis reveals that incentives alone cannot overcome foundational issues in data integrity and user-centric design, necessitating refinements for broader viability.[105] Independent assessments emphasize that systemic errors, affecting thousands of records, have amplified opportunity costs, diverting resources from potential enhancements to crisis management.[77]Looking ahead, expansions scheduled for 2025, including functionality as a driver's license from March and broadened private-sector linkages like deposit account integrations from April, aim to elevate utility through seamless digital verification and potential AI-driven analytics for personalized services.[106][107] Government projections anticipate higher integration rates via platforms like Apple Wallet by mid-year, coupled with real-time empirical tracking through penetration dashboards to monitor outcomes.[108][103] Success will hinge on addressing root causes of underutilization, such as bolstering security protocols and fostering trust through transparent error rectification, to transition from incentive-dependent rollout to organically adopted infrastructure.[67]