Seishain, Keiyaku, Haken, and Arubaito: Japan's Employment Categories
Japanese employers sort workers into four categories: seishain, keiyaku shain, haken, and arubaito. Which one appears on your offer letter shapes your bonus, your paid leave, when you enroll in Employees' Pension, and how closely an immigration officer reads your next visa renewal.
Procedures, fees, and requirements can change. Confirm current details at the Ministry of Health, Labour and Welfare (MHLW). This article is general information, not legal, tax, or immigration advice; for your specific case, consult a licensed shakai hoken roumushi (社会保険労務士, labor and social insurance attorney) for contract-classification or benefits questions, or an immigration lawyer or gyōseishoshi (行政書士) for visa-renewal-specific risk.
Overview
None of the four categories, except haken, has a single controlling statutory definition.1234 Each is instead a labor-market convention: a bundle of expectations shaped by which statute's protections and obligations attach to it.
These categories and the statutes behind them are national law. There is no ward, city, or prefectural variance in how seishain, keiyaku, haken, and arubaito are defined or regulated.1235 The shakai hoken (social insurance) enrollment thresholds covered later in this article are also set nationally, by MHLW and the Japan Pension Service, not by individual employers or localities.67
The sibling article How the Japanese Labor Market Works already places seishain at the center of Japan's shushin koyo (lifetime employment) and nenko chingin (seniority-based pay) system. This article does not repeat that framing; it goes deep on how the four categories differ in practice.
At a glance
| Category | Japanese term | Typical contract length | Typical hiring route |
|---|---|---|---|
| Seishain | 正社員 | Indefinite (no fixed term) | New-graduate (shinsotsu) hiring, mid-career direct hire |
| Keiyaku shain | 契約社員 | Fixed-term, commonly renewed annually | Direct hire, often for a defined role or project |
| Haken | 派遣社員 | Fixed-term placement, employed by a dispatch agency | Registration with a haken-moto (dispatch agency), then agency-arranged placement at a client company |
| Arubaito | アルバイト | Hourly, often with no fixed end date but frequently short-tenure in practice | Direct hire, informal or part-time recruiting channels |
"Seishain" itself carries no fixed definition in Japanese law. The commonly used working definition combines three elements: an indefinite-term labor contract, full-time scheduled hours, and direct employment rather than agency-mediated placement.4
Seishain: The Permanent-Employee Track
Seishain is understood, by convention rather than statute, as combining three things: no fixed term in the labor contract, full-time scheduled working hours, and direct employment by the company the person actually works for, not through a dispatch agency.4
Because seishain has no statutory definition, the exact bundle of benefits, bonus eligibility, and job-security protection a given "seishain" role carries is set by each employer's own work rules (shugyo kisoku) and employment contract. Those employer rules sit on top of a floor set by the Labor Standards Act and other labor statutes; they cannot go below it.48
Why seishain is the default-aspiration tier
How the Japanese Labor Market Works already covers why seishain functions as the system's reference point, through shushin koyo and nenko chingin. This section does not re-derive that framing. What matters here is narrower: seishain is the category the other three are measured against on bonus, benefits, and job security, in the comparison later in this article.
Keiyaku Shain: Fixed-Term Contract Employment
A keiyaku shain works under a labor contract with a fixed term, directly with the employer rather than through a dispatch agency. In practice, the term is commonly renewed annually, though the length itself is not fixed by statute.2
When a worker's fixed-term contracts with the same employer, taken together, exceed 5 years of continuous service, the worker gains a right under the Labor Contracts Act to demand conversion to an indefinite-term contract. This is the muki tenkan (無期転換) right.2
Once the worker makes this request, for the day immediately following the current contract's expiry, the employer is deemed by operation of law to have accepted it: no separate employer approval is needed.2 The converted labor conditions carry over unchanged from the immediately prior fixed-term contract, apart from the term itself becoming indefinite, unless a separate agreement states otherwise.2
The 5-year conversion rule at the category level
The exact citation is Labor Contracts Act (労働契約法), Article 18, Paragraph 1. The rule took effect April 1, 2013, and applies to fixed-term contracts commencing on or after that date.2
The 5-year count resets, a "cooling off," if there is a blank period of 6 months or more between contracts. This cooling mechanism is written directly into the statute itself (Article 18, Paragraph 2), not left to ministerial discretion.2 For a run of fixed-term contracts totaling less than 1 year before the blank period, a shorter proportional cooling period applies, set out in an implementing MHLW ordinance rather than in Article 18 itself (as of 2026-07; confirm current figures with the Ministry of Health, Labour and Welfare).2
The cooling-off mechanism itself is not an evasion tactic. Article 18 was drafted to include it.2 Separately, timing a non-renewal (yatoidome) specifically to keep a worker from reaching the 5-year mark is evaluated case by case under a different legal test, and outcomes have gone both ways in practice. See "The 5-year and 3-year clocks are sometimes 'reset' with a contract gap" below for how courts have actually applied this.
This article keeps the 5-year rule at category-placement level: what it is and why it matters for where keiyaku sits in the hierarchy. The exception categories for advanced-degree and high-income specialists, the full mechanics of the employer-avoidance pattern, and the yatoidome case law are covered in depth in a dedicated future article on the 5-year conversion rule.
Haken: Dispatch Employment
A haken shain is employed by a dispatch agency, the haken-moto (派遣元事業主), but performs work under the direction and supervision of a separate client company, the haken-saki (派遣先), which does not itself employ the worker.93 The governing statute is the Act on Securing the Proper Operation of Worker Dispatching Businesses and Protecting Dispatched Workers, commonly called the Worker Dispatching Act.39
The agency-client split and why it matters
Payroll and shakai hoken (health insurance and Employees' Pension) enrollment obligations sit with the haken-moto, the entity that legally employs the worker. The haken-saki directs day-to-day work but is not the insured employer of record.9
This same split is where visa-sponsorship responsibility lands: with the dispatch agency, not the client company where the work actually happens. See "Haken's dual-employer structure confuses both workers and immigration reviewers" in Good to know, and Visa renewal implications below.
The 3-year placement limit
A client company may not continuously accept worker dispatching services for the same work at the same place of business beyond 3 years, counted per business establishment (事業所単位). This is the Worker Dispatching Act, Article 40-2.3 The establishment-level 3-year period can be extended in further 3-year increments if the client follows a defined procedure, including hearing the opinion of the majority labor union, or a worker representative where none exists, at that business establishment.3
Separately, and in addition to the establishment-level limit, a client company may not continuously accept the same individual dispatched worker in the same organizational unit for more than 3 years. This individual-level limit, Article 40-3, has no extension procedure available.3
After the 3-year placement period, the client must end the placement, rotate the worker to a different organizational unit, or offer the worker direct employment. The full statutory mechanics of this transition are covered in a dedicated future article on Japan's three main labor statutes.
The gap some clients use before re-accepting the same worker is not written into Articles 40-2 or 40-3 themselves. MHLW's own client-facing guideline calls resuming a placement after a gap, for the specific purpose of avoiding the extension procedure, "contrary to the purport of" the Act, and subject to administrative guidance (shido) from the labor bureau.103 That is a real enforcement exposure, but it is administrative guidance, not published case law, unlike the parallel muki tenkan situation on the Labor Contracts Act side.
Arubaito: Part-Time and Hourly Work
Arubaito is an hourly-paid employment category, not itself defined by statute, conventionally associated with students, workers between jobs, and retirees supplementing pension income.4 No source defines "arubaito" by statute, for the same reason none defines "seishain": neither is a legal category.
A foreign national on a ryugaku (student) visa working arubaito-type jobs does so under a separate work-hours permission (資格外活動許可), capped at 28 hours per week, with an exception allowing up to 8 hours per day during the school's long vacation periods.11 Going over the cap is a status-of-residence issue, not a labor-law technicality.
Who arubaito status typically covers
This tier commonly covers students working under the permission above, workers transitioning between jobs, and retirees drawing pension income who take on supplementary hourly work. No single statute enumerates this list; it reflects labor-market convention rather than a legal category.4
Comparing the Categories: Bonus, Benefits, Leave, Pension, and Visa Renewal
| Category | Bonus | Paid leave | Pension and health insurance | Visa-renewal pattern |
|---|---|---|---|---|
| Seishain | Near-universal biannual bonus, by employer practice, not legal mandate8 | Full statutory schedule12 | Employees' Pension and Employees' Health Insurance via employer67 | Reads as the most stable file for renewal review |
| Keiyaku shain | Often reduced or discretionary8 | Full statutory schedule12 | Employees' Pension and Employees' Health Insurance via employer67 | Fixed-term nature draws closer scrutiny of stability (practitioner-observed pattern, not an ISA-stated rule)13 |
| Haken | Typically none8 | Full schedule, or prorated below 30 hours/week14 | Via haken-moto once above the shakai hoken threshold; below it, National Pension6715 | Agency-not-client sponsorship draws scrutiny of duty-content match13 |
| Arubaito | Typically none8 | Prorated below 30 hours/week and reduced scheduled days14 | Via employer once above the shakai hoken threshold; below it, National Pension6715 | Generally does not itself satisfy the work-sponsoring status requirement11 |
Bonus and benefits eligibility
Bonus (shoyo) payment is not mandated by the Labor Standards Act or any other statute. An employer owes no legal bonus obligation unless the employment contract or work rules create one, at which point the employer must follow what it has specified.8
Seishain roles near-universally include a biannual (summer and winter) bonus as a matter of employer practice, not legal mandate. Keiyaku shain bonus eligibility is frequently reduced or fully discretionary by comparison, and haken and arubaito workers typically receive no bonus at all.8 This is a structural pattern; no labor-survey statistic on prevalence is cited here or should be assumed.
Where a part-time or fixed-term worker's job content and scope of duties match a comparable regular employee's, the employer may not treat that worker differently because of their part-time or fixed-term status, including on bonus. Where duties genuinely differ, the employer still may not create a gap that is unreasonable given the difference in duties, responsibility, and scope of assigned changes.5
The governing articles are the Part-Time and Fixed-Term Employment Act, Article 8 (prohibition of unreasonable treatment differences, balanced treatment) and Article 9 (prohibition of discriminatory treatment where duties and assignment scope are functionally equivalent, equal treatment).51 These are two distinct legal tests, not one undifferentiated "equal pay" rule: Article 8 asks whether a gap is unreasonable given real differences; Article 9 forbids any gap once duties and assignment scope are functionally identical.
Paid leave
Statutory annual paid leave (nenkyu kyuka) under the Labor Standards Act applies to workers in all four categories, once a worker has been continuously employed for a qualifying period and has attended a required proportion of scheduled working days. The entitlement is not limited to seishain.12 The exact citation is Labor Standards Act, Article 39, Paragraph 1.12
A worker with fewer scheduled working days than a full-time worker, a common arubaito and part-time pattern, receives paid leave prorated to their own schedule under a "proportional grant" (比例付与) mechanism, but only where weekly scheduled hours are under 30 AND either weekly scheduled working days are 4 or fewer, or, if days are not set weekly, annual scheduled working days are 216 or fewer (as of 2026-07; confirm current figures with the Ministry of Health, Labour and Welfare). A worker who works 30 or more hours per week receives the same full leave schedule as a full-time worker, regardless of category.14
Pension and social-insurance enrollment
Seishain and keiyaku shain workers, meaning workers directly employed on an indefinite or fixed-term basis at typical full-time schedules, enroll in Employees' Pension Insurance (kosei nenkin, 厚生年金保険) and Employees' Health Insurance as a matter of course through their employer.67
Haken and arubaito workers enroll in the same employer-based shakai hoken system, through the haken-moto for dispatch workers, only once they cross a defined enrollment threshold. Below it, they fall to National Pension (kokumin nenkin, 国民年金) as a self-paying "Category 1 insured" (第1号被保険者), or, if a dependent spouse of someone enrolled in Employees' Pension, "Category 3 insured" (第3号被保険者) with no separate premium obligation.156
| Term | Reading | Meaning |
|---|---|---|
| 社会保険 | shakai hoken | "Social insurance"; here, health insurance and Employees' Pension enrollment jointly.6 |
| 厚生年金保険 | kosei nenkin hoken | Employees' Pension Insurance, the employer-based pension scheme.7 |
| 国民年金 | kokumin nenkin | National Pension, the base-layer scheme for those not enrolled in an employer pension.15 |
| 第1号被保険者 | dai-ichi-go hihokensha | Category 1 insured person: pays their own National Pension premium directly (self-employed, unemployed, or under-threshold part-time workers).15 |
| 第3号被保険者 | dai-san-go hihokensha | Category 3 insured person: the dependent spouse of a Category 2 (employer-pension-enrolled) insured person, with no separate premium.15 |
| 特定適用事業所 | tokutei tekiyo jigyosho | "Specified applicable business establishment": the employer-size threshold designation that triggers short-time-worker enrollment.6 |
Current shakai hoken enrollment requirements for short-time (part-time, arubaito, haken) workers, all of which must be met simultaneously:
| Requirement | Current threshold | As of | Source |
|---|---|---|---|
| Weekly scheduled working hours | 20 hours or more | 2026-07 | 67 |
| Monthly prescribed wage | ¥88,000 or more (excludes bonuses, overtime pay, commuting allowance, family allowance) | 2026-07 | 7 |
| Employer size | 51 or more employees enrolled in Employees' Pension Insurance | 2026-07 | 67 |
| Expected employment duration | Continuous employment expected to exceed 2 months | 2026-07 | 7 |
| Student status | Must not be a student, with exceptions for those on leave, night-course students, and others nearing graduation | 2026-07 | 7 |
These thresholds sit on an active, government-published phase-in schedule, not a permanent fixed rule (as of 2026-07).
This is a legislated, dated phase-in confirmed against MHLW's own expansion microsite and the Japan Pension Service, not a proposal under discussion. Anyone currently below threshold on employer size should expect to cross it as their employer grows into scope, even without changing jobs.
| Effective date | Change | Source |
|---|---|---|
| October 2026 | The ¥88,000/month wage requirement is removed. Any worker meeting the hours, employer-size, and duration tests enrolls regardless of wage level. | 76 |
| October 2027 | Employer-size threshold drops to 36+ employees. | 6 |
| October 2029 | Employer-size threshold drops to 21+ employees. | 6 |
| October 2032 | Employer-size threshold drops to 11+ employees. | 6 |
| October 2035 | Employer-size threshold is eliminated; all employer sizes covered, subject to the remaining hours, duration, and student conditions. | 6 |
These effective dates and figures are current as of 2026-07.
In practice, removing the wage requirement mostly matters for below-minimum-wage-equivalent, low-hour cases: working 20 hours a week at minimum wage in most prefectures already clears ¥88,000 a month.76 This schedule is administered by MHLW and the Japan Pension Service under a legislated multi-year phase-in, not a single named act this article cites by title.
Visa renewal implications by category
The Immigration Services Agency's own published guideline for status-of-residence change and period-of-stay renewal centers its review on whether the applicant has assets or skills sufficient to support an independent livelihood, evaluated at the household level, and on whether the applicant's actual activity still matches their status of residence and complies with labor law.13
The guideline's own text does not name contract type, seishain versus keiyaku versus haken versus arubaito, as a distinct scored factor; it retains broad discretionary language about "comprehensively considering all circumstances."13 Immigration lawyers and gyoseishoshi who handle renewal cases describe a consistent pattern even so: keiyaku's fixed-term nature and haken's agency-not-client sponsorship structure both tend to invite closer scrutiny of employment stability and duty-content match. Treat this as a practitioner-observed pattern, not a line item written into the ISA's own guideline.
Nothing here is a quoted rule from the Immigration Services Agency's own guideline text. It is what immigration lawyers and gyoseishoshi report seeing in practice, and it is worth knowing even though it is not written down as a scored criterion.
For haken specifically, the review process for a dispatch worker's status can include direct ISA contact with both the haken-moto (the visa sponsor) and the haken-saki (where the work is actually performed), to confirm duty content and activity status. A mismatch between the sponsoring agency's stated business and the client-site duties is a documented review point.13
Arubaito-type hourly work does not itself satisfy the work-sponsoring activity requirement for most work-based statuses of residence. This is distinct from a student-visa holder's permitted supplementary work, which exists under its own separate permission precisely because a student's status is not work-sponsoring in the first place.11
This section keeps to the category-level pattern. Full renewal-procedure mechanics are covered in a dedicated future article on extension of period of stay.
Good to know
Arubaito rarely qualifies you for a work-sponsoring visa status
A work-visa holder whose actual income relies mainly on arubaito-type part-time work is a red flag at renewal, because arubaito does not itself satisfy the work-sponsoring activity requirement of most statuses. This is distinct from a student-visa holder's permitted supplementary work, which is authorized under a wholly separate permission (資格外活動許可) rather than treated as the primary sponsoring activity.1113
The risk is one of conflating two different legal functions: the arubaito category and the student-visa supplementary-work permission. Mixing them up invites an activity-status mismatch at renewal review.
Haken's dual-employer structure confuses both workers and immigration reviewers
The dispatch agency, the haken-moto, not the client company where the work actually happens, is the legal employer, the visa sponsor, and the shakai hoken enrollee of record.913 Payroll and social-insurance enrollment obligations sit with the haken-moto by definition of the dispatch relationship.
A mismatch between the sponsoring agency's stated line of business and the worker's actual client-site duties is a documented immigration review point. Workers and employers on both sides of a haken placement benefit from keeping the agency's registered business scope and the worker's real duties clearly aligned.
The 5-year and 3-year clocks are sometimes "reset" with a contract gap, and that practice is legally contested
Under the Labor Contracts Act's muki tenkan (5-year) rule, the cooling-off mechanism itself is lawful and written directly into the statute: a blank period of 6 months or more, or a shorter proportional period for runs of contracts under 1 year, resets the accumulated-period count. It is not, by itself, an evasion tactic; Article 18 was drafted to include it.2
What is legally exposed is different: timing a non-renewal (yatoidome) specifically to prevent a worker from reaching the 5-year mark. That is evaluated case by case under the separate yatoidome doctrine, where a non-renewal must have objective and reasonable grounds and be socially appropriate once the worker has an established expectation of renewal.2
Outcomes vary by fact pattern. The Tokyo High Court, on November 1, 2022, in the "Nihon Tsuun" case, upheld an employer's non-renewal because the worker's contracts included explicit non-renewal clauses and the worker had not yet reached the 5-year threshold when the relationship ended; the court found no established renewal expectation and no unlawful evasion on those specific facts.16 Treat this as "courts apply real, fact-specific scrutiny to non-renewals timed around the 5-year mark, with results that go either way," not as proof the practice is safe, and not as proof it is outlawed.
Under the Worker Dispatching Act's 3-year rule, the picture is different in kind. The 3-month-plus-one-day cooling period is not written into the placement-limit articles themselves; Articles 40-2 and 40-3 contain no cooling or reset language.3 It derives instead from MHLW's implementing interpretation.
MHLW's own client-facing guideline (派遣先が講ずべき措置に関する指針, Ministry of Labour Notification No. 138 of 1999, most recently amended by MHLW Notification No. 379 of 2016) states explicitly that a client resuming acceptance of the same dispatched worker after a cooling gap, for the specific purpose of avoiding the placement-extension procedure, is "contrary to the purport of" the Act's period-limit provision, and such conduct is subject to administrative guidance from the labor bureau.103 As of 2026-07, this is confirmed administrative guidance, not an area with a leading published court precedent the way the muki tenkan side has. It is an active administrative-enforcement target, not folk wisdom about a loophole, but it should not be described as struck down by courts or as legally unregulated.
Visa-renewal caution is about the officer, not just the rule
The categories and thresholds covered in this article are nationally uniform, but individual Immigration Services Agency case officers exercise real discretion in weighing a given contract type's stability, per the guideline's own "comprehensively considering all circumstances" language.13 Treat this as a practical caution about case-by-case officer judgment, not a jurisdictional variance between wards or prefectures.
The ISA's own guideline reserves broad discretionary authority even where an applicant meets every listed criterion. A reader whose classification, benefits eligibility, or renewal outlook is contested or unclear is better served by a professional read of their specific case than by this article's general patterns.