Januar Jahja & Partners

Januar Jahja

Founding Partner

Mr. Jahja is the founding partner of Januar Jahja & Partners. Described as a “profoundly intelligent lawyer” (WTR 1000 2013), he has more than forty years of experience in the field of Indonesian Intellectual Property law. Mr. Jahja has extensive IP litigation experience before both the Jakarta Commercial Court and the Indonesian Supreme Court, having won numerous landmark cases at all levels of the Indonesian court system. Mr. Jahja is licensed to practice law in Indonesia, as well as before the Indonesian Patent and Trademark Office.

These days, his practice focuses primarily on counseling clients with complex IP issues, including trademark cancellation actions, trademark infringement cases and oppositions. Mr. Jahja is licensed to practice law in Indonesia, as well as before the Indonesian Patent and Trademark Office.

Recognition: Mr. Jahja has received numerous awards and recognition for his continued excellence, including: IP Star (Managing IP 2014, 2015); RecommendedLegal 500 (2014, 2015, 2016); Leading LawyerAsialaw Profiles (2014, 2015, 2016); Leading IndividualWTR 1000 (2013, 2014, 2015), among others.

Languages: Indonesian, English

Walter Simandjuntak


Described as “among the leading IP lawyers in Indonesia,” (Asialaw Profiles 2016), Mr. Simandjuntak is a former Director of Patents and Copyright/Industrial Design at the Indonesian IP Office. Now a partner at JJP, his practice focuses primarily on client counseling for copyright, patent and industrial design matters, as well as enforcement issues. Prior to joining Januar Jahja & Partners in 2005, Mr. Simandjuntak held various high-level positions within the Indonesian government. More specifically, he served as the Director of Patents (1997-2001) and then the Director of Copyright and Industrial Design (2001-2005) at the Intellectual Property Office in the Department of Law and Human Rights. Additionally, Mr. Simandjuntak served as an Intellectual Property Rights (IPR) Delegate of the Indonesian Government at the World Trade Organization (WTO) Ministerial Meetings in Doha (2001) and Cancun (2003). Mr. Simandjuntak is licensed to practice law in Indonesia, as well as before the Indonesian Patent and Trademark Office.

Recognition: Mr. Simandjuntak’s extensive expertise has earned him the honor of being named as a “Leading Lawyer” by Asialaw Profiles (2014, 2015, 2016) and “Recommended” by Legal 500 (2015).

Languages: Indonesian and English

Prudence Jahja


A registered IP Consultant in Indonesia with experience working for IP firms in Europe and the United States, Ms. Jahja co-manages the Firm’s International Department. In this regard, her practice focuses primarily on trademark prosecution and litigation, as well as enforcement matters, including website takedowns. Ms. Jahja holds a bachelor degree in Economic and Business Law from Atma Jaya University in Jakarta, Indonesia and earned a Master’s Degree in Intellectual Property and Competition Law from the Munich Intellectual Property Law Center (MIPLC) at the Max Planck Institute in Munich, Germany. As part of her studies in Germany, Ms. Jahja interned at the German Intellectual Property Law firm of Preu Bohlig & Partner. After receiving her LL.M, she worked in the New York office of the Intellectual Property firm Frommer Lawrence & Haug, LLP. She also served as a judicial intern for the Chief Judge of the U.S. Court of Appeals for the Federal Circuit in Washington, D.C. Ms. Jahja is licensed to practice law in Indonesia, as well as before the Indonesian Intellectual Property Office.

Recognition: Mrs. Jahja’s work has been recognized by various outlets such as the Legal 500, WTR 1000 and Chambers Asia Pacific. Most recently, she was described as a “rising star” by Asialaw Profiles (2016), which quoted a client as stating, “She provides an excellent and thorough service in trade mark disputes and counseling.”. She was also named a “Ranked Lawyer” and an “Associate to watch” by the 2015 edition of Chambers Asia Pacific, which stated that Mrs. Jahja “is praised by interviewees, who note that ‘she is absolutely top-notch’ as she ‘provided round-the-clock service.’” She has also been named a ASEAN IPR SME Heldesk “Expert”.

Similarly, WTR 1000 (2015) noted that “[c]lients are effusive in their praise of European-educated, US-experienced Prudence Jahja,” leading her to be named a Leading Individualdue to her growing reputation in the field. One client was quoted as saying of Mrs. Jahja: “Prudence could not be any more superb a lawyer; she provided literally round-the-clock service for months on end in a complex trademark lawsuit, during which she made our team feel entirely comfortable. We trusted her completely and the end result was exactly what we needed. We are excited to have future matters in Indonesia so that we can work with her again.”


Languages: Indonesian, English

    Nena Esse Nurasifa

    Junior Associate

    Ms. Nurasifa assists with both non-contentious and contentious trademark matters, including warning letters, oppositions, and litigation. She is a 2015 graduate of the Faculty of Law at the University of Indonesia, where she was the National Champion of Piala Abdul Kahar Mudzakkir V, FH UII, National Moot Court Competition (Intellectual Property case/theme) as well as the vice-head of publication for the Law Student Association in Legal Practice.

    Languages: Indonesian, English.

    Andrew Diamond

    Foreign IP Consultant

    As a Foreign IP Consultant, Mr. Diamond co-manages the Firm’s International Department and coordinates all outgoing work for the Firm’s domestic clients. Described as a “‘notable practitioner’” (Chambers Asia Pacific 2014) with “‘a professional background in dealing with foreign clients’” (Legal 500 2014) “who provides excellent service” (IP STARS 2015), his practice focuses on IP litigation strategy, anti-counterfeiting and enforcement matters, both online and offline. Prior to joining Januar Jahja & Partners, Mr. Diamond worked as an associate in the New York office of Venable LLP, an AmLaw 100 firm. While there, Mr. Diamond worked in the Commercial Litigation Group, where his practice focused on assisting clients in class action and securities fraud defense, as well as compliance with the Foreign Corrupt Practices Act (FCPA). Mr. Diamond has a J.D. from Brooklyn Law School and an LL.M in Intellectual Property and Technology Law from the National University of Singapore (NUS). He is licensed to practice law in the State of New York.

    Recognition: Mr. Diamond has been recognized by such outlets as Legal 500 (“Recommended” 2014), Asialaw Profiles (2015), and Chambers Asia Pacific (2014, 2015), which named him a “Ranked lawyer” and placed him in Band 1 for “Intellectual Property: Foreign Legal Consultants – Indonesia” for 2015. He has also been named a ASEAN IPR SME Heldesk “Expert”. In March 2015, he presented on Indonesia to the spring meeting of the Pharmaceutical Trade Marks Group (PTMG).

    Languages: English, Indonesian.


    Juanitasari Winaga

    IP Consultant

    Ms. Winaga’s practice as an IP Consultant focuses primarily on trademark prosecution for both international and domestic clients. Prior to joining JJP, Ms. Winaga worked in the education and food and beverage (F&B) sectors for more than 10 years, most recently with a large Indonesian food manufacturing company. She holds a bachelor degree in Education from Atma Jaya University and a Master’s Degree in Business Management from Bina Nusantara University (Binus). Registered as an IP consultant with the Government of Indonesia, Ms. Winaga is licensed to practice before the Indonesian Directorate General of Intellectual Property (DGIP).

    Languages: Indonesian, English, Chinese (Mandarin).