Tsuyoshi Sueyshi
Attorney-at-law
Tokyo, Japan
Summary
👤
Senior🎓
Top SchoolTsuyoshi Sueyshi is an IP-focused attorney and patent agent based in Tokyo with over 15 years’ experience handling high-stakes patent litigation, licensing, invalidation trials and technology disputes for domestic and international clients. A chemist by training (BSc and PhD from the University of Tokyo) who transitioned from R&D in Li-ion batteries and catalysts to patent prosecution and litigation, he uniquely combines deep technical expertise in physical chemistry and solid-state physics with courtroom and JPO practice. He has argued precedent-setting cases — including an IP High Court enlarged panel matter that reversed JPO guidance on patent term extension — and regularly represents clients across pharmaceuticals, biotech, semiconductors, telecommunications and performance chemicals. Recognized repeatedly by IAM, Chambers and Lexology Index, he is as comfortable drafting complex licensing deals as litigating infringement and appeals. He also contributes to open-source engineering projects, bringing practical backend and test-automation experience from work on the popular AngleSharp HTML/CSS parser to his systematic, detail-oriented approach to IP disputes. This blend of laboratory, patent-prosecution and litigation experience gives him a rare ability to translate nuanced science into persuasive legal strategy.
15 years of coding experience
5 years of employment as a software developer
Ph. D., Graduate school of Science, Department of Chemistry, the University of Tokyo, Ph. D., Graduate school of Science, Department of Chemistry, the University of Tokyo at 東京大学
Chinese
Stackoverflow
2,572reputation
468kreached
17answers
0questions
angular
top-5%
Github Skills (19)
parserator10
parser10
testing10
standard-library10
dotnet-core10
html10
c-library10
common-library10
csharp10
asp-net-core9
angular9
linq8
asp-net6
css6
asp-net-mvc6
Programming languages (8)
Github contributions (5)
AngleSharp/AngleSharp
Dec 2015 - Oct 2021
:angel: The ultimate angle brackets parser library parsing HTML5, MathML, SVG and CSS to construct a DOM based on the official W3C specifications.
Role in this project:
Back-end Developer & Test Automation Engineer
Back-end Developer & Test Automation EngineerContributions:7 commits, 4 PRs, 10 comments in 5 years 11 months
Contributions summary:Tsuyoshi primarily contributed to bug fixes and implemented new features within the AngleSharp library, a HTML/CSS/SVG parser. Their work addressed issues related to text encoding, multipart form data handling, and select element behavior, enhancing the library's robustness. They also added new test cases to improve the project's testing coverage. These modifications focused on core parsing functionalities and form submission aspects, demonstrating a strong understanding of the library's internal workings.
c-sharphtml5parserlinqultimate
tsu1980/Mamemaki.HolidayJp
Nov 2019 - Mar 2025
Calculate Japan public Holidays
Contributions:1 PR, 27 pushes, 1 branch in 5 years 4 months
calculatepublic-holidays
Find and Hire Top DevelopersWe’ve analyzed the programming source code of over 60 million software developers on GitHub and scored them by 50,000 skills. Sign-up on Prog,AI to search for software developers.