Japan - Domestic OHNO & PARTNERS

OHNO & PARTNERS is an IP boutique law firm established on May 1 2000.

In Japan, there are two qualification systems for professionals who handle legal issues concerning intellectual property: attorney at law and patent attorney. Formerly, it was common for a client to secure the services of a patent firm (run by patent attorneys) when obtaining IP rights such as patents and trademarks, and to secure the services of a law firm (run by attorneys at law) for enforcement.

However, if a company wishes to achieve a significant result from the enforcement of an IP right, we believe that it is necessary to have litigation in mind even from the prosecution stage. Based on this viewpoint, it is clear to us that a one-stop integrated service for all stages of IP rights is necessary. OHNO & PARTNERS has 14 patent attorneys and four design and trademark attorneys in addition to nine attorneys at law working in close cooperation every day to maximise the value of clients’ IP assets.


The firm’s practice is recognised globally. In recent years, IAM has recommended OHNO & PARTNERS for litigation and transactions and Managing Intellectual Property and Asia IP have ranked the firm in the patent and trademark contentious categories. Chambers Global has consistently ranked the firm for IP practice, and Asian Legal Business ranked the firm in the patents and trademarks/copyright categories.

Expertise and strength

Since its foundation, the firm has represented clients in many difficult cases that would be impossible for other firms to handle, especially regarding cutting-edge technologies such as information technology, communication, semiconductor technology, biotechnology, nanotechnology and other cross-industry technologies.

The firm actively tackles unresolved legal issues, and as a result has established new case law before the IP High Court and the Supreme Court. For example, the firm was at the centre of a fair, reasonable and non-discriminatory licensing dispute between Samsung and Apple in Tokyo.

In addition, the firm has experienced many large-scale multinational parallel litigations and is adept at handling such complexity.

Its vast experience in intense IP litigation ensures that the firm has litigation in mind in situations other than enforcement. This is what the firm calls its ‘pre-litigation mindset’.

For example, the firm is experienced in tailoring claims of a pending patent application to cover the products of an opposing party before litigation or negotiation. Or, when appropriate, it helps clients to file a correction trial for patented claims in parallel with an ongoing dispute in order to strengthen the client’s position.

The firm’s pre-litigation mindset stands out in IP due diligence. For example, in the event of mergers and acquisitions, IP due diligence – especially patent due diligence – is becoming increasingly important for assessing the value of the party to be acquired. The strength of its IP portfolio and that of competitors’ portfolios as well as licensing situations have considerable impacts on the business after mergers and acquisitions, and serious evaluation has become increasingly important. The firm has gained expertise in providing such evaluations.

Centred on its broadly appreciated expertise in IP litigation offered by attorneys with diverse backgrounds and experience, OHNO & PARTNERS is expanding the scope of its services to include a wide range of pre-litigation counselling.

To truly support clients in achieving their business goals – this is what the firm takes seriously.

Main address

Marunouchi Kitaguchi Building
21st Floor
Tokyo 100-0005

Contact details

E: info@oslaw.org
T: +81 3 5218 2330
F: +81 3 5218 2332
W: www.oslaw.org

Professional contacts

Seiji Ohno, Managing partner
E: info@oslaw.org

Recommended individuals at this firm

Seiji Ohno
Japan: Domestic

Ken-ichi Katayama
Japan: Domestic


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Issue 89