When your freelance consulting business or startup reaches steady profitability, you will inevitably hear about Hōjinnari ( 法人成り )—the process of transitioning from a sole proprietorship into an incorporated company.
Incorporating in Japan carries distinct legal, operational, and tax consequences. While corporations face stricter bookkeeping, mandatory director salary rules, and unavoidable base taxes, they also change how expenses, profits and owner remuneration are taxed.
Here is how corporate taxes work for small businesses in Japan, whether you choose a Kabushiki Kaisha (KK) or a Godo Kaisha (GK).
1. KK vs. GK: Does Your Corporate Structure Affect Taxes?#
When incorporating in Japan, founders almost always choose between two corporate structures:
- 01KK · Kabushiki kaisha
A company with shares
A familiar structure for outside equity investment. Formation includes notarisation of the articles.
- 02GK · Gōdō kaisha
A membership company
Flexible internal governance and no notarisation of the articles. It is not a US-style pass-through for Japanese tax.
Choose for ownership, investment and governance needs. A GK does not automatically receive a lower corporate tax rate.
KKs and GKs are both corporations for Japanese tax purposes. Their applicable rates depend on factors such as size, ownership, location and income, rather than the KK/GK label alone.
2. The Corporate Tax Stack#
Unlike personal income tax (which scales progressively up to 45% + 10% residence tax), corporate profits in Japan are taxed using a combination of national and local corporate taxes:
- 01Company revenue
Pay business costs
Include operating expenses, deductible director pay and the employer’s insurance contributions.
- 02Company profit
Pay corporate taxes
National and local taxes apply to retained profit. Fixed local levies can still apply in a loss year.
- 03Director’s salary
Pay personal taxes
Salary has its own income tax, residence tax and employee insurance share. Company profit is not personal take-home pay.
A corporate rate and a personal marginal rate measure different things. Model both sides before deciding to incorporate.
Eligible small corporations can use a 15% national corporate tax rate on the first ¥8 million of taxable profit, with exceptions; the standard national rate is 23.2%. Local taxes and fixed levies are additional. Fiscal years beginning from April 1, 2026 also need consideration of the defense special corporate tax and its allowance. See NTA corporate rates and JETRO’s combined-tax tables.
3. The Unavoidable ¥70,000 Base Tax ( 均等割 )#
One of the most important rules every founder must understand:
A sole proprietor with no taxable income may owe no income tax, although other income and obligations still matter.
A Japanese corporation does not enjoy this luxury.
Even if an active company has no revenue or posts a loss, your local municipality and prefecture will bill your company an annual Equalization Per-Capita Levy of approximately ¥70,000 per year (¥50,000 municipal + ¥20,000 prefectural for companies with capital of ¥10M or less and 50 or fewer employees).
If you maintain an active Japanese corporation, you must budget for this baseline maintenance fee every single year.
4. Director’s Remuneration ( 役員報酬 , Yakuin Hōshū)#
When you own your own company, you cannot simply transfer profits to your personal bank account whenever you want. Japan has exceptionally strict rules regarding how directors are paid.
The “Periodic Equal Amount” Rule ( 定期同額給与 )#
- The Rule: Ordinary annual revisions to regular director pay are generally made within three months of the start of the fiscal year, subject to the statutory rules.
- The Catch: The usual deductible-pay route is regular remuneration at equal periodic amounts. Permitted revisions and other deductible-pay categories exist; arbitrary changes can lose the company’s deduction. See the NTA director-pay rules.
- Why this exists: The tax office prevents business owners from waiting until month 11 to see how much profit the company made and then writing themselves a sudden massive bonus to wipe out corporate tax liability!
Warning: If you pay yourself an arbitrary bonus mid-year without pre-registering it with the tax office via the Pre-Determined Salary Notification ( 事前確定届出給与 ), the company cannot deduct that bonus as a business expense, but you will still be personally taxed on it!
The Double-Deduction Advantage#
Despite these restrictions, paying yourself a director’s salary creates a powerful tax benefit:
- At the corporate level: Qualifying director remuneration is a deductible business expense, reducing corporate taxable profit.
- At the personal level: As an employee receiving a salary, you receive the statutory Employment Income Deduction ( 給与所得控除 ), giving you up to ¥1,950,000 in personal deductions that sole proprietors cannot claim!
5. Mandatory Social Insurance ( 社会保険 )#
By law, corporate workplaces with covered workers, including many one-person companies with a paid director, must enroll in the corporate social insurance system. Check the Japan Pension Service’s workplace coverage rules:
- Health Insurance & Welfare Pension: Determine coverage and complete the required workplace and worker registrations.
- Cost Split: Approximately 30% total, with the company paying 15% and the director paying 15%.
- Deductibility: The employer’s half is a fully deductible business expense for the corporation.
6. When Does It Make Sense to Incorporate (Hōjinnari)?#
Should you stay a sole proprietor or establish a KK/GK?
| Consideration | Sole Proprietor (個人事業主) | Corporation (KK / GK) |
|---|---|---|
| Startup Cost | ¥0 (Free filing at tax office) | Registration and other formation costs; KK usually costs more |
| Minimum Base Tax | ¥0 if no profit | ~¥70,000/year even at a loss |
| Max Income Tax Rate | Top marginal rates of 45% income + usually 10% residence, plus surtax | National and local taxes; no universal 34% cap |
| Bookkeeping Complexity | Moderate (Blue Return software) | High (Often benefits from a Japanese tax accountant / 税理士 ) |
| Ownership & Administration | Business and owner are the same taxpayer | Separate entity, company records and payroll obligations |
| Social Insurance | National Health (expensive at high profit) + Pension | Corporate Shakai Hoken (mandatory 50/50 match) |
Model Your Own Break-Even Point#
Profits around ¥8–10 million are often used as a starting point for an incorporation comparison, but there is no automatic tax-saving threshold.
Compare personal take-home pay, profit left in the company, both insurance shares, local levies, accounting fees and formation costs. Also consider how you will eventually withdraw retained profits. A lower rate on retained company profit alone does not establish that incorporation saves money.