Japan: Domestic

In recent years Japanese rights holders have exhibited a newfound eagerness to monetise and enforce their patents – as opposed to simply sitting on them as part of a defensive, wait-and-see approach. While this shift in attitude is generating plenty of work for lawyers at the moment, significant increases in the size of in-house teams could be of concern for patent attorneys in the future. Inbound work from China remains a notable source of revenue.

Firms: litigation

  • Abe, Ikubo & Katayama
  • Anderson Mori & Tomotsune
  • Nakamura & Partners
  • STW & Partners
  • TMI Associates 
  • YUASA and HARA 
  • Aoyama & Partners
  • Mori Hamada & Matsumoto
  • Nagashima Ohno & Tsunematsu
  • Nishimura & Asahi
  • The Tokyo-Marunouchi Law Offices

Firms: prosecution

Firms: transactions

  • Abe, Ikubo & Katayama
  • Anderson Mori & Tomotsune
  • Mori Hamada & Matsumoto
  • Nagashima Ohno & Tsunematsu
  • Nakamura & Partners
  • TMI Associates 
  • YUASA and HARA 

Abe, Ikubo & Katayama

It is about quality, not quantity, for Abe, Ikubo & Katayama; impeccable performances across the contentious/non-contentious divide are the hallmark of its highly specialised team, which “thrives on the most challenging and complex mandates” in life sciences, electronics and telecoms. Recently strengthened by the addition of a biotechnology expert, the prosecution set is captained by Hiroshi Kobayahsi. A former chief patent counsel at Dow and Pfizer’s Japanese operations, he has been instilled with “immense commercial expertise” from his time in-house, which continues to “inform his creative and pragmatic advice”. “Diligent and honest, Kobayashi always achieves optimal results and is a crucial ally for those seeking patent term extensions.” In contentious settings, Eiji Katayama, Mami Hino and IAM Patent 1000 debutant Junichi Kitahara are a force to be reckoned with. “A deft strategist who gets ahead of future trends, managing partner Katayama boasts strong connections globally.” He is qualified to practise both in Japan and in New York – as is the case for his “responsive and diligent” colleague Hino, who springs into action when infringers violate customers’ rights. Maintaining a watchful eye on potential rivals, the proactive lawyer “settles cases long before they go to court”. Backed up by two decades of experience, Kitahara is an assertive litigator renowned for shielding a high-profile combatant in the smartphone wars; he earns a place this year following the extensive time he has spent fighting in the trenches for pharmaceutical and telecoms players.

Anderson Mori & Tomotsune

One of Japan’s largest law firms, Anderson Mori & Tomotsune serves up an all-inclusive patent platter to an assortment of hungry rights holders across myriad industries. Famed for its flawless drafting of patents in the biotech and chemical fields, the prosecution division leverages this on the international stage and works with clients to file their patents globally and advise on subsequent technology transfer agreements. Armed with biochemistry expertise and the ability to decipher the most complex of inventions, Makoto Ono stands out from the crowd. For the resourceful litigation set, infringement, inventor remuneration and ownership disputes are all fair game. The diverse talents of 437 attorneys are available to the IP practice leader Yasufumi Shiroyama, a courtroom sharpshooter who fights tooth and nail for domestic and multinational devotees. A prolific writer, he also lectures on IP law at the prestigious Tokyo University Law School. New York and Japanese-qualified Yoshikazu Iwase is a favourite among US corporations, which value his experience in a US setting (he previously worked in Finnegan’s Reston office). Making a resounding effect in infringement suits, he knows how to put the Japan Patent Office (JPO) in its place too, taking it to taskin revocation suits, and patentability and validity disputes.

Aoyama & Partners

A patent prosecution powerhouse best known for its influence in the pharmaceutical space, Aoyama files over 6,000 patent applications globally each year. With 60% of its national applications originating from major domestic innovators, it knows how to push a patent through – both at the JPO and at patent offices internationally; a network of 3,000 foreign associates ensures that the group is entirely clued-up on worldwide IP trends. Striding confidently into the contentious realm for the first time this year, the set has established a litigation department headed by vice president Hiroshi Tamura. Alongside his staunch representation of Nichia, Shionogi and Brahms in the Japanese limbs of multi-jurisdictional disputes, he is also a prosecution sage, who always takes into consideration future challenges when drafting a patent.

Asamura Patent Office PC

Having been in the game for over 125 years, Asamura’s globalist prosecution practice maintains a fine balance between inbound and outbound work; two teams of experts – split over mechanical/electrical and chemical divisions – file some 12,000 applications at the JPO and 15,000 overseas every year. Although it is sought after by patrons all over the world, its biggest fans are Asian, European and North American titans such as Chevron, Scania and Hitachi. Those wanting to know what all the fuss is about should speak to senior managing partner Ken Kanai.

Fukami Patent Office

Distinguishing itself with its global approach and skilled patent craftsmanship, Fukami Patent Office stands tall in electrical, mechanical and material manufacturing briefs, dialling in applications for its loyal following. With exposure to the patent environments of over 180 jurisdictions and a list of happy international customers dating back half a century, the team boasts a prodigious talent for foreign-originated instructions and has a global network to match. A newly minted international patent and design division formally enshrines a path that the set has been forging for decades. Chairman Hisao Fukami is best placed to provide more information.

ITOH International Patent Office 

Upheld by patent attorneys registered in China, Korea and the United States, ITOH’s panoramic view of these key venues for Japanese rights holders underpins the squad’s seamless foreign filing capacity. Famed for its electrical and mechanical prowess, the 62-strong unit is a highly influential technical ensemble bolstered by an in-house English-to-Japanese translation unit. Japanese and US patent attorney Tadashige Itoh is an excellent first port of call for rights holders.

Kyowa Patent and Law Office 

Celebrating 110 years of practice in 2018, Kyowa continues to share its far-sighted strategic insight on the Japanese market. Spread across mechanical, electrical and chemical sections, 12 partners lead a harmonious choir of patent attorneys and lawyers in prosecution and keep possible enforcement needs covered from the start. Fluid inter-departmental collaboration is a major strength and fosters a hospitable environment for protecting inter-disciplinary inventions – a hallmark of the team’s esteemed service. Managing partner Hiroshi Nagai is top dog of the Kyowa pack.

Mori Hamada & Matsumoto

One of Japan’s Big Four law firms, full-service operation Mori Hamada & Matsumoto’s bedrock lies in life sciences and information technology, but the side mounts impressive performances elsewhere; this is combined with an extensive network of offices spanning much of East and Southeast Asia, which cements the outfit as a discerning choice for multi-jurisdictional patent work. Start-ups, multinationals and research institutions count on its aptitude in the field – particularly in transactional instructions, where a much-lauded M&A department keeps the group’s eye on the ball in IP-rich deals. Having honed his craft in US operations, Yutaka Miyoshi is sought after for his finesse in cross-border matters. He shares his legal insight as a member of an IP policy study group and of a Ministry of Economy, Trade and Industry committee tasked with drafting unfair competition laws.

Nagashima Ohno & Tsunematsu

Facing down international challenges with the backing of New York and outposts across the Association of Southeast Asian Nations (ASEAN) region, Nagashima Ohno & Tsunematsu draws on a diverse legal toolbox to jump hurdles for its construction and high-tech client base. Facilitating the introduction of domestic operations to new markets is also a talent; the Nagashima professionals match strategy to their clients’ commercial ambitions while simultaneously cutting through the inevitable mountain of red tape. Honing his patent knowledge over 30 years as a judge, German and English speaker Ryoichi Mimura deploys his expertise and experience to bring an end to any battle. Fellow contentious maven and Waseda Law School professor Masato Tanaka is also a former judge. When not sharing his considerable expertise as an appeal examination counsellor at the JPO, he counsels loyal patrons through pre-litigation stages. Takahiro Yamauchi is a vital ally to technology-heavy operations caught in a clash. Yoshimi Ohara and Shunji Matsuda – both shrewd negotiators – complete the offering. A keen player in alternative dispute resolution, Ohara is a frequent fixture overseeing global arbitrations, while Matsuda bolsters his appeal with extensive knowledge of sports and entertainment law.

Nakamura & Partners

One-stop shop Nakamura & Partners taps a well of technical expertise to provide clients with comprehensive, tailored solutions and strategies. Receiving frequent training to keep their skill sets in shape, the line-up excels across biotech, chemical, mechanical and IT disciplines; the firm sponsors many of its professionals in pursuing their legal education abroad, thus ensuring the sustainability of the talent within its ranks. When not outsmarting adversaries, Kazuhiko Yoshida shares his astute legal insight as an author of a series of articles on court judgments and their impact on IP law and practice; Yoshio Kumakura boasts a stellar track record in must-win patent litigations; and Koichi Tsujii takes command, informing his contentious solos with all-encompassing commercial acumen.

Nishimura & Asahi

Securing iron-clad rights protection across Japan, East and Southeast Asia, all the way to the Middle East, Japan’s biggest law firm Nishimura & Asahi is a “well-established outfit that is excellent for patent litigation and IP consultancy”. The patent practice boasts close ties to illustrious foreign associates worldwide, which enables it to launch enforcement campaigns for clients or shield them from attack in any jurisdiction at a moment’s notice. Drawing on celebrated M&A and corporate practice groups, the IP contingent effortlessly satisfies demand for a robust transactional capacity; it brings its best poker face to every negotiation. Hitomi Iwase stands poised and ready to field initial enquiries.


Although it delivers a cradle-to-grave patent service, OHNO remains permanently prepared for battle. When drafting patents, the set assesses any potential weak point that rivals could expose and moves to reinforce it before it can be exploited. When matters do get heated, the firm is in its element, summoning its talent for resolving complex fair, reasonable and non-discriminatory disputes, as well as a host of other points of contention in the patent realm. Managing partner Seiji Ohno brings ample firepower to courtroom conflicts and gives nothing away in licensing negotiations. In non-contentious instructions, Ken-ichi Katayama adds 12 years of research to his 18 years as a patent attorney. Also armed with a doctorate in electronics, he is an undisputed authority in his field.

Ohtsuka Patent Office 

Ticking all the right boxes on a diverse technical spreadsheet, Ohtsuka chalks up win after win in electronics, medical device and biotech applications, aided by its state-of-the-art case management system and a stand-out back-office team. Regional and global portfolio management is the lifeblood of the ensemble, to whom specialised procedures and tight deadlines are never a problem. A litigation squad is always on standby to take any issue in the courtroom and settle it decisively. With over 45 years in practice, managing partner Yasunori Ohtsuka has seen everything there is to see in the electronics sector and elegantly traverses contentious and non-contentious matters.

Okuyama & Sasajima

The secret to long-lasting client-attorney relationships is clear communication and Okuyama & Sasajima’s squad of native English speakers and in-house translators diligently fosters this with foreign clients, removing any hint of ambiguity in its correspondence. As a result, it has won the repeat patronage of US and European operations – such as the University of North Carolina – which depend on the side’s dogged pursuit of success in biotech briefs. Principal Shoichi Okuyama is the key contact.


Making its sophomore appearance in the IAM Patent 1000, RYUKA continues to garner excellent feedback from those who have benefited from its excellent performances, proactive approach and “stellar advice on the Japanese patent system”. This unfaltering work ethic – coupled with innovative patent visualisation capabilities – enables the outfit to procure more and more patents in the earliest stages of the development cycle and to maximise the value of the portfolios they take on. The corps stands out for electronics and telecoms players, for whom its forward-thinking insight holds considerable appeal. President Aki Ryuka is the man for interested parties to seek out.

Seiwa Patent & Law

“Superb leadership and unwavering quality can be felt at every level of Seiwa’s patent practice.” An accomplished team implements rigorous quality controls and every patent that goes through the firm warrants a second pair of eyes to ensure the Is are dotted and the Ts crossed. A 100-strong team of patent attorneys calls on the wisdom of four US and European consultants, who guarantee factual and linguistic accuracy in every event. General manager of the design department, Minako Mizuno is a patent prosecution specialist and a former chief patent examiner at the JPO.

Shiga International Patent Office

From flourishing start-ups to major multinationals, rights holders find comfort in the astute guidance of Shiga International’s world-class line-up; eight former JPO examiners, 360 technical experts and seven native English speakers have all bases covered. A fluent prosecution ability is complemented by a highly respected capacity in litigation settings. Multinationals seeking either service have the option of working with individuals comfortable working in English, French, German, Chinese and Korean. President Yasuhiko Murayama stands ready to bring prospective customers in from the cold.

Shusaku Yamamoto Law Offices

Shusaku Yamamoto dispenses a remarkable patent offering from its Osaka, Tokyo and Fukuoka offices; a broad following – including recent winners of Nobel Prizes for physiology, medicine and chemistry – count on its 160-strong staff to handle anything they send its way. Close supervision and meticulous attention to detail explain this loyalty, with the management maintaining an omniscient eye over clients’ commercial, regulatory and patent requirements to maintain coherence across the board. Although disputes are rare for devotees of the set, the firm’s rigorous approach to conflict avoidance ensures the best interests of rights holders are borne in mind whatever the eventuality. Firm founder Shusaku Yamamoto assesses each case individually, relying on nearly 40 years of experience to inform his approach.

SOEI Patent & Law Firm

Earning its place in the IAM Patent 1000 for the first time, SOEI earns effusive feedback for its modern, innovative approach. Eschewing the byzantine structure common to traditional Japanese firms, the unit thrives on a collegial culture and “streamlined internal processes; everything is automated”, while high-tech systems efficiently file, generate and issue any necessary documentation for doing business, whether with clients or at the patent office. Clearly the novel approach is paying off: “SOEI’s filings are increasing despite the overall shrink in the Japanese market.” Three Japanese offices and one in Washington DC provide robust coverage, but last year the set extended this coverage with a new Bangkok bureau – its first in the ASEAN region. Vice president Yoshinori Shimizu is a key name.

Sonderhoff & Einsel Law and Patent Office

With English, German, and Chinese speaking professionals advising on IP, tax and accounting matters, Sonderhoff is renowned for its cross-cultural and cross-disciplinary proficiency. The company offers its sage counsel to patrons from across Europe and East Asia and plays host to smooth and unhindered communication. A formal association with an office in Beijing contributes to the firm’s reputation as a one-stop shop for maintaining and expanding Chinese portfolios. Managing partner Felix-Reinhard Einsel is the name to note.

STW & Partners

Full-service operation STW provides a 360-degree perspective on patent matters; taking every potential hurdle into consideration, the set develops a patent strategy tailored to every clients’ goals. Among a cadre of highly skilled attorneys – many of whom were previously big names in Mori Hamada & Matsumoto – Wataru Sueyoshi and Hajime Watanabe receive high acclaim. Both are well-known for taking no prisoners in the courtroom, as well as for their prolific writing on IP issues. Sueyoshi has spent 35 years honing his craft, while Watanabe trails only slightly behind with 30 years of experience and is admitted to the bars in Japan, New York and Chicago.

SUGIMURA & Partners 

“A top choice for Japanese work,” the newly rebranded SUGIMURA & Partners is a “strong and safe pair of hands in prosecution and goes the extra mile to accommodate patrons in any way possible”. With expertise that “stretches across all technical disciplines”, the 180-strong line-up “provides a timely and accurate” rights protection service and has recently welcomed Koji Sugimura to its executive team. As a legislative affairs officer at the JPO, he was an instrumental figure in revising the Patent Act and while at Nishimura & Asahi, added numerous contentious wins to his résumé – knowledge and experience he now employs when spearheading the group’s forays into contentious territory. He manages the firm alongside Kenji Sugimura, a mechanics and architectural engineering maven known for his cutting-edge analyses of Japanese, European and US IP markets.

The Tokyo-Marunouchi Law Offices

Over little more than a decade, Tokyo-Marunouchi’s small-but-perfectly-formed patent offering has rapidly built itself a reputation as a major player in dispute resolution for a predominantly foreign client base. In the last 12 months, the ensemble has taken on a new patent attorney, broadening its already far-reaching technical faculties and has seen a spike in requests for its talents in pharmaceutical disputes. Putting on an impressive performance in these instructions, former judge Yukio Nagasawa knows everything there is to know about intellectual property; he has spent 19 years on the bench and 11 years as a professor at Tokyo University.

TMI Associates 

Among Japan’s biggest firms, TMI boasts nine overseas offices too, recently strengthening its international coverage with the opening of a London outpost. Bolstered by the appointment of two new patent partners, 80 patent attorneys and 60 attorneys at law form a home team that earns its place in the big league and excels across the full patent spectrum. Yoshiyuki Inaba captains the ever-expanding practice. With over four decades of experience, he offers “unique insights into Japanese patent law” and enjoys “warm relationships” with foreign associates. Formerly in-house at Microsoft, newly ranked Toyotaka Abe knows how to push through any obstacle at the JPO. He marries commercial acumen with resounding technical nous to deliver impeccable results in accordance with his clients’ business plans.


The “highly specialised” patent team at YUASA and HARA forges custom-made solutions to the most complex patent problems, which it combines with similarly tailored tax and accounting advice. Judicial experience and technical excellence in chemistry, electronics and mechanics are the defining features of the incredibly proficient troop. Drawing on an unparalleled international network made possible through participation in both TerraLex and UniLaw networks, the firm is an established international player and a discerning choice for clients of all stripes. A respected voice in the legal communities of both Japan and the United States, Kozo Yabe leads the IP set. He is currently vice chair of the Law School Centre of Japan Federation of Bar Associations and an adjunct professor at the University of Illinois.

Other recommended experts

With valuable experience as an IP High Court judge, Sakurazaka Law’s Harumi Kojo knows every trick in the contentious book and exploits this to summon creative solutions to her own courtroom challenges. Founder and managing partner of KUBOTA, Eiichiro Kubota is a highly experienced patent attorney and lawyer with a broad range of contentious and transactional experience. Since departing OHNO & PARTNERS, Kan Otani has established Roppongidori Patent & Trademark Attorney and has made a name for himself as a champion of start-ups and venture capital-backed companies. Operating from his base at City-Yuwa Partners, Hideo Ozaki is a keen strategist with a varied practice encompassing litigation and licensing. Yoshitaka Sonoda fronts the litigation practice at Sonoda & Kobayashi Intellectual Property Law. Armed with a structural engineering background and 28 years in IP practice, he receives plaudits for his silver-tongued negotiation skills. From eponymous outfit Takahashi Yuichiro Law Office, former Toshiba in-house counsel Yuichiro Takahashi prosecutes patents for a list of top-billing electronics outfits.

Individuals: litigation

  • Eiji Katayama - Abe, Ikubo & Katayama
  • Yoshio Kumakura - Nakamura & Partners
  • Ryoichi Mimura - Nagashima Ohno & Tsunematsu
  • Seiji Ohno - OHNO & PARTNERS
  • Yasufumi Shiroyama - Anderson Mori & Tomotsune
  • Wataru Sueyoshi - STW & Partners
  • Yoshikazu Iwase - Anderson Mori & Tomotsune
  • Junichi Kitahara - Abe, Ikubo & Katayama
  • Yukio Nagasawa - Nagasawa Patent Firm
  • Masato Tanaka - Nagashima Ohno & Tsunematsu
  • Koichi Tsujii - Nakamura & Partners
  • Hajime Watanabe - STW & Partners 
  • Kozo Yabe - YUASA and HARA
  • Kazuhiko Yoshida - Nakamura & Partners
  • Yoshiyuki Inaba - TMI Associates
  • Hiroshi Kobayashi - Abe, Ikubo & Katayama
  • Harumi Kojo - Sakurazaka Law Offices
  • Eiichiro Kubota - KUBOTA
  • Yutaka Miyoshi - Mori Hamada & Matsumoto
  • Yoshimi Ohara - Nagashima Ohno & Tsunematsu
  • Koji Sugimura - SUGIMURA & Partners 
  • Yuichiro Takahashi - Takahashi Yuichiro Law Office
  • Hiroshi Tamura - Aoyama & Partners
  • Takahiro Yamauchi - Nagashima Ohno & Tsunematsu

Individuals: prosecution

Individuals: transactions

  • Yoshikazu Iwase - Anderson Mori & Tomotsune
  • Eiji Katayama - Abe, Ikubo & Katayama
  • Eiichiro Kubota - KUBOTA
  • Shunji Matsuda - Nagashima Ohno & Tsunematsu
  • Yoshimi Ohara - Nagashima Ohno & Tsunematsu
  • Seiji Ohno - OHNO & PARTNERS
  • Hideo Ozaki - City-Yuwa Partners
  • Kozo Yabe - YUASA and HARA
  • Kazuhiko Yoshida - Nakamura & Partners