IP Assignment Agreement (知的財産権譲渡契約書)

Transfers ownership of patents, copyrights, designs, and trade secrets created at work to the employer. Aligns with Patent Act Article 35 and Copyright Act Article 15.

By Emmanuel Gendre

Founder, SaiyouTeam · 12 years recruiting in Japan

Last reviewed: May 2026 · Aligned with the Restrictive covenant workflow in Japanese HR practice

Official sources

This template is built on the following primary Japanese government sources. Open each link to verify the underlying rule against the issuing authority.

e-Gov 法令検索 - Patent Act, Article 35 (employee inventions) Article 35 of the Patent Act governs employee inventions. Companies can claim ownership from the start under work rules, but must provide reasonable benefit (相当の利益) to the inventing employee.
e-Gov 法令検索 - Copyright Act, Article 15 (works made in employment) Copyright in works created by employees in the scope of employment vests automatically in the employer. No separate assignment is needed for copyright (unlike patents).
Japan Patent Office (特許庁) The Japan Patent Office is the agency administering patents, utility models, designs, and trademarks. Their guidelines clarify employee-invention compensation requirements.

Reference

What the IP Assignment Agreement (知的財産権譲渡契約書) is

An IP Assignment Agreement (知的財産権譲渡契約書) is the agreement under which the assignor (typically employee, contractor, or developer) transfers ownership of specified intellectual property to the assignee (the company). Japanese law treats different IP types differently: copyright in works made by employees in the scope of employment vests automatically in the employer under Copyright Act Article 15, but patents, utility models, designs, and trade secrets require explicit assignment from the inventor (employee) to the company under Patent Act Article 35. The 2015 Patent Act amendment allowed companies to claim ownership of employee inventions from the start under properly-drafted work rules, subject to providing reasonable benefit (相当の利益) to the inventing employee.

When to use

When to use this document

Employees in R&D, software development, design, and creative roles where IP is a meaningful output of their work
Contractors and external developers producing custom work product
New hires in industries where patents are central (manufacturing, biotech, semiconductors, software)
Acquisitions where individual inventors' rights need to be cleared for the acquirer
Joint development arrangements where IP allocation between parties needs to be explicit

Mandatory items

What to include

Identity of assignor (employee or contractor) and assignee (the company)
Specific IP being assigned, or a forward-looking assignment of all IP created during employment within the company's business scope
Effective date of assignment
Compensation (相当の利益) for patent assignments: lump sum, ongoing royalty, or part of salary with explicit attribution
Moral rights treatment: copyright moral rights cannot be transferred but can be subject to a non-exercise commitment
Cooperation obligations: signing assignment papers, providing technical information, prosecuting patents in the company's name
Representations and warranties: assignor has clean title, has not previously assigned the same IP, and IP does not infringe third-party rights
Carve-outs: assignor's pre-existing IP, personal projects clearly outside the scope of employment, IP developed entirely on personal time and equipment without company resources

Legal basis

Legal background and constraints

Different IP types have different default rules in Japan. Copyright in works made by employees in the course of employment vests automatically in the employer under Copyright Act Article 15; no separate assignment is required, though the agreement should still acknowledge moral rights. Patents and utility models require explicit assignment from the inventor (the individual employee) under Patent Act Article 35; the 2015 amendment allows companies to claim ownership from inception via work rules, conditional on providing 相当の利益 (reasonable benefit) to the inventor. Trade secrets are protected under the Unfair Competition Prevention Act when they meet the three criteria (secrecy management, usefulness, non-public). The Japan Patent Office (特許庁) publishes detailed guidelines on the 相当の利益 calculation and the procedural requirements for claiming employee inventions.

Frequently asked

Common questions about the IP Assignment Agreement

Does the employer automatically own employee inventions and software?

Copyright in software and other works created in the course of employment vests automatically in the employer under Copyright Act Article 15; no separate assignment is needed. Patents do not work the same way: under Patent Act Article 35, the right to file for a patent originally belongs to the inventor (the employee). The company can claim that right from the start via properly-drafted work rules and consideration, but explicit documentation is required.

What compensation is required for patent assignment?

Patent Act Article 35 requires "reasonable benefit" (相当の利益) for the inventor whose patent is assigned to the employer. The benefit can be monetary (lump sum, royalty, milestone bonus) or non-monetary (career advancement, recognition, training opportunities), but must be set out in the work rules or assignment agreement and applied consistently. Insufficient or arbitrary compensation is the most common ground on which inventors challenge an assignment.

Can pre-employment IP be excluded from the assignment?

Yes, with proper carve-outs. The assignment agreement should list pre-existing IP that the employee retains, ideally with a schedule of the specific items (existing patents, software, designs) and the date created. Without an explicit list, the employer might inadvertently claim rights to pre-employment work, which can lead to disputes and unwinding of the assignment.

What about moral rights of the author?

Moral rights in Japan (the right to be identified as author, the right to maintain the integrity of the work) cannot be assigned. They remain with the original author indefinitely. Employers manage this through a non-exercise commitment (不行使特約): the author agrees not to exercise their moral rights against the company's use of the work. The non-exercise commitment is enforceable and is standard practice in IP assignment agreements.

Is IP assignment retroactive?

Forward assignments cover IP created from the agreement date onward. Past IP can be assigned, but the agreement must explicitly identify and address it. For new hires, the cleanest pattern is a forward-looking assignment from the employment start date plus a separate inventory and assignment of any IP the employee brings from prior work that the company will use.

About the author

Emmanuel Gendre

Founder, SaiyouTeam · TechieCV K.K.

Emmanuel advises small and mid-sized companies (SMBs) on HR and recruiting in Japan. He brings 12 years recruiting in Japan as a Recruitment Consultant placing IT professionals, plus prior experience hiring engineers across EMEA as a Google recruiter. Restrictive covenant-related paperwork is something he handles regularly with his SMB clients in Japan, so he built this template as part of that advisory work and uses it himself when those conversations come up.

For case-specific contract matters, Emmanuel works with licensed Japanese professionals (社会保険労務士 and 弁護士). This template is a planning tool used in those conversations, not a substitute for professional advice on an individual case.

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Important. This template is provided for general planning purposes only and is not a substitute for professional advice. Japanese contract law is complex and case-specific. Before issuing this document in any non-routine situation, consult a qualified labor lawyer (弁護士) or Certified Social Insurance and Labor Consultant (社会保険労務士).

IP Assignment Agreement (知的財産権譲渡契約書)

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Official sources

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