About Us

Oshima & Partners was established in 1983.

Since its establishment, the firm has represented many of Japan’s leading companies with regard to intellectual property matters and has provided services to companies and patent firms internationally.

We are constantly exposed to the latest technologies in a variety of technical fields and have accumulated knowledge in a wide range of technical fields. We are working hard to draft specifications to meet the needs of clients in every technical field.

Our staff members have various technical backgrounds and are able to meet the needs of our clients. It is our belief that we have to have adequate technical knowledge to properly represent our clients in intellectual property matters. It is also important to communicate with our clients to better represent our clients.

We are one of a small number of Japanese patent firms which provide services to both domestic and foreign clients in a well-balanced manner. This is desirable not only for our business viewpoint but also for our ability to serve our clients from a broader perspective.

  • Breakdown of Patent Applications in Our Firm
    Breakdown of Patent Applications in Our Firm

    Three segments are split about 30% each and are well-balanced.

  • Major Countries of Application
    Major Countries of Application

    To date, we have filed applications in more than 30 countries and territories.


Masahiko Kimura
September 1983
TEL:+81-3-3556-1861 / FAX:+81-3-3556-1871
IP Building, 2-20, Kanda-Jimbocho, Chiyoda-ku,Tokyo,101-0051,Japan
7 patent attorneys, 7 patent engineers, 3 drawing technicians, 11 office clerks
Domestic and foreign “patent”, “utility model”, “design”, and “trademark” applications, prosecution, prior art searches, disputes, and consulting services
Areas of expertise
Transportation Machinery (Automotive), General Machinery and Industrial Machinery, Household Items, Telecommunications and Networks, Civil Engineering and Construction, Medical Equipments, Chemicals and Pharmaceuticals, Electronics and Electronic Circuits, Biotechnology, Semiconductors, Manufacturing plants, etc. *We have a wealth of experience in machinery, including automobiles and automobile parts in particular.


September 1983 Oshima & Associates was established
November 1993 As a result of merger with Narushima Intellectual Patent Office (Patent Attorney Mitsuo Narushima) the firm’s name was changed to Oshima & Narushima.
July 2011 The firm shifted from a private firm to a partnership firm (English name changed to Oshima & Partners)

Office Features

  • Extensive experience in foreign applications

    We are versed in both technical knowledge and language skill as we prepare applications in the Japanese language for both domestic clients and foreign clients, and applications in the English language for domestic clients. We are trained to communicate with our partners and clients both domestic and foreign.

  • Teamwork and proactive proposals

    We work as a team to produce the best result based on sound reasoning for each task. We listen to the needs and desires of our clients but do not hesitate to make proactive proposals.

  • Drawings and translations are prepared in-house.

    Drawing drafting and translation are done in-house to ensure proper attention and high quality results.

  • Availability on short notice and careful due date management

    In patent matters, keeping due dates is highly essential. We maintain a due date management system that allows us to keep all due dates. There are times urgent work is needed. We are prepared for such occasions and ready to get the work done on short notice.


We are available for various consultations regarding intellectual property matters.
Please feel free to contact us.