ABOUT
Founded in 2004 as a California-based boutique IP litigation firm, Masuvalley & Partners has grown into a cross-border full-service legal partner spanning Asia and Europe.
Founded in California in 2004, Masuvalley & Partners was a boutique law firm specializing in high-value IP litigation for Asian companies. In the early days, we gained a reputation for successfully defending the IP rights of Japanese, Chinese and Korean companies in the U.S. Federal Courts.
In 2010, we expanded our practice to provide a full range of IP-related services, including patent, trademark and design filings, and began coordinating filings in over 20 jurisdictions worldwide. This marked the beginning of our transformation from a boutique litigation law firm to a global IP and legal services provider.
Since 2010, Masuvalley & Partners has established strategic offices in China, Japan and Southeast Asia to provide local IP filing and enforcement services. A key focus area in the region is anti-counterfeiting. We have strengthened our crackdown on counterfeiting in 12 Asian countries. Most notably, we have established a UK branch. Under an alternative business structure (ABS), we have created a full- service legal entity that blends IP lawyers with corporate, regulatory and dispute resolution experts.
The evolution of our UK business reflects our strategic transformation from an IP specialist to a true full-service international law firm providing end-to-end support to clients looking to expand from the UK to Japan, Vietnam and back again.
Our work is closely aligned with the transformation of the global economy, from a new focus on comprehensive US tariffs to multilateral commitments under the CPTPP. As companies navigate the complex challenges of international trade and IP protection, Masuvalley & Partners is here to serve as your legal and strategic partner, addressing these challenges through smart, scalable solutions.
Masuvalley & Partners’ history is one of agility, insight and international collaboration, driven by our mission to support companies in an era of global integration.
MESSAGE from CEO
At Masuvalley & Partners, our journey began in 2004 in San Diego, California, with a clear mission: to serve as a reliable bridge between Asia and the Western legal world, particularly in the realm of intellectual property. What started as a small, IP-focused law firm has now grown into a multinational legal platform with offices in six countries and trusted clients in over 20 jurisdictions.
Our early focus on litigation gave us a deep understanding of risk, enforcement, and legal strategy. But as our clients’ needs evolved, so did we. We expanded our services to cover IP filings, portfolio management, and, eventually, broader legal services ranging from corporate advisory to international compliance. Each of our offices—in Tokyo, Bangkok, Suzhou, Ho Chi Minh City, and most recently, London—was opened not just as a geographical expansion, but as a commitment to building local teams that understand local laws, languages, and cultures.
Our newest venture in the UK marks a significant turning point. As a full-service law firm under the UK’s Alternative Business Structure (ABS) framework, we now provide legal support far beyond IP. This includes commercial transactions, employment matters, cross-border M&A, and international dispute resolution. With this step, we position ourselves not only as IP specialists but as a strategic partner for businesses operating globally.
Today, we are proud to offer a legal network that combines deep regional knowledge with cross-border execution. Whether you are a European company seeking protection in Asia, or an Asian client expanding into Western markets, our multilingual, multinational legal team is here to walk with you.
Thank you for your trust. We look forward to helping you navigate complexity with clarity and confidence—wherever your business takes you.
Masuvalley Group CEO
Yoshi Masutani
HISTORY
Masuvalley & Partners was originally established in 2004 in San Diego, California, as a law firm specializing in intellectual property (IP). At its inception, the firm primarily focused on representing Asian clients—particularly from Japan, China, and South Korea—in patent litigation and trademark disputes in the United States. Through years of practical experience in cross-border legal battles, Masuvalley quickly gained a reputation for its strategic litigation capabilities and deep expertise in U.S. intellectual property law.
Recognizing the growing demand for end-to-end IP services beyond litigation, the firm expanded its scope in 2010 to include prosecution and portfolio management, establishing the Tokyo office as a hub for Japanese domestic and outbound filings. This marked a shift from a litigation-heavy practice to a more holistic IP firm capable of handling everything from filing to enforcement and monetization.
In 2012, Masuvalley opened its Bangkok office, beginning its expansion into Southeast Asia. By 2017, the firm launched its Suzhou office in China, establishing a solid foothold to directly interface with CNIPA and support clients in handling patent filings, oppositions, invalidations, and anti-counterfeiting operations. In 2019, the Ho Chi Minh City (HCMC) office in Vietnam was opened to support ASEAN-wide trademark filings and brand enforcement campaigns.
In 2024, leveraging two decades of cross-border legal experience, Masuvalley & Partners established its latest branch in London, UK. This office is structured as a full-service law firm under the UK’s Alternative Business Structure (ABS) framework, enabling it to offer a broad range of legal services beyond IP—such as corporate law, commercial contracts, employment, M&A, compliance, and international dispute resolution. By incorporating both IP lawyers and general practice solicitors, the London office serves as a gateway for UK clients entering Asia and vice versa.
Currently, the firm operates across six jurisdictions: USA, Japan, China, Thailand, Vietnam, and the UK. Across these locations, the firm employs over 15 bilingual attorneys and maintains a multinational legal license structure that allows it to practice and coordinate legal matters across borders with high efficiency and compliance.
With this extensive global network, Masuvalley & Partners is uniquely positioned to support businesses with:
Legal expansion from the UK into Japan and Vietnam;
Representation of Asian clients facing legal risks in the US or Europe;
Intellectual property protection and monetization strategies;
Trade, tariffs, and regulatory advisory in the context of economic frameworks such as CPTPP and emerging global trade compliance issues.
What began as an IP litigation boutique in California has evolved into a multi-jurisdictional legal platform, serving as a strategic hub for international law and cross-border business. Masuvalley & Partners continues to thrive by adapting to global legal shifts, aligning with the commercial realities of our clients, and delivering practical solutions that transcend borders.