Call for Expressions of Interest – Mainz Masterclass In International Adjudication

Applications are invited for participation in the First Mainz Masterclass in InternationalAdjudication on 9 April 2027, organized by the Mainz International Adjudication Center (MAIAC) at Johannes Gutenberg University Mainz, Germany. The Masterclass will be held by Professor Campbell McLachlan KC (University of Cambridge) and will be devoted to“Evidence in International Adjudication”.

The Format
Each year, a distinguished scholar or practitioner is invited to engage intensively with a groupof 10–15 advanced students, doctoral candidates, and postdoctoral researchers on a key topicin international dispute settlement. The Masterclass consists of two sessions, a morning and anafternoon session, and will comprise a duration of approximately six hours in total.

The Masterclass 2027
The topic of the Inaugural Masterclass is “Evidence in International Adjudication”.

The preparation and presentation of evidence plays as crucial a role in international adjudication as it does in domestic proceedings. Cases are at least as likely to be won or lost on the facts as they are on the law. Yet, in contrast to the position in national legal systems, the legal rules and principles applicable to evidence before international tribunals are often vague and uncertain. They leave much to the initiative of the parties and the discretion of the tribunal. International adjudication brings together parties, counsel, and tribunal members from different legal traditions, with different approaches to evidence gathering and presentation. How should this system be made to work in order to ensure that each party’s case is presented most effectively and the tribunal is placed in the best position to decide the dispute?

Professor McLachlan will draw upon his extensive academic research and his two decades of experience as an international arbitrator, particularly in disputes between sovereign States and private parties. He will engage with the masterclass participants on both the legal issues concerning the admissibility and treatment of evidence and on the legal craft involved in the effective presentation and testing of evidence at the hearing, using practical examples from reported cases. The morning session will concern the production and presentation of factual evidence: documentary and witness. The afternoon session will concern the use and testing of the testimony of expert witnesses.

The Lecturer
Professor Campbell McLachlan KC is a leading international lawyer, specialising in international dispute resolution.

He was elected in 2023 to the Professorship of Law (1973 Chair) at the University of Cambridge and serves as Professor of International Dispute Resolution, Fellow of Trinity Hall, and Fellow of the Lauterpacht Centre for International Law.

A native of New Zealand, he earned an LLB (Hons) from Victoria University of Wellington and a PhD from the University of London. He also holds the Diploma cum laude of The HagueAcademy of International Law.

Prior to his return to academia, Professor McLachlan enjoyed a distinguished legal career inLondon, where he was a partner at Herbert Smith and headed the firm’s International Law Practice Group. Throughout his career, he has represented sovereign states, corporations,international organisations and regulatory bodies in complex international litigation andarbitration proceedings. He was appointed King’s Counsel in 2007 and continues to combineacademic scholarship with an active practice in international dispute resolution.

He is a Member (on the nomination of New Zealand) of the Permanent Court of Arbitration and of the Panel of Arbitrators at the International Centre for the Settlement of InvestmentDisputes (ICSID); as well as a Member (on the joint proposal of the UK and the EU) of thePanel of Independent Chairs of Arbitral Tribunals under the UK-EU Cooperation Agreement. He is an Associate Member of Essex Court Chambers (London) and of Bankside Chambers (Auckland & Singapore). He is frequently appointed presiding arbitrator of international arbitral tribunals.

Professor McLachlan is internationally recognised for his contributions to public and private international law, foreign relations law and international arbitration. He has held numerous leadership positions within the international legal community, including serving as President of the Australian and New Zealand Society of International Law, and was elected to the Institut de Droit International in 2015. He also serves as Editor-in-Chief of The Cambridge LawJournal and Joint Editor-in-Chief of the ICSID Review – Foreign Investment Law Journal and is a Specialist Editor of Dicey, Morris & Collins on the Conflict of Laws (16th edn, 2022).

His publications are among the leading works in the field and include Foreign Relations Law (CUP, 2014) International Investment Arbitration: Substantive Principles (2nd edn, OUP, 2017, with Laurence Shore and Matthew Weiniger), and The Principle of Systemic Integration inInternational Law (OUP, 2024). In 2024, he delivered the General Course at The HagueAcademy of International Law, published as On the Interface between Public and PrivateInternational Law (Brill, 2025).

The Annual International Adjudication Lecture
The Masterclass is organized by the MAIAC in combination with an Annual Lecture inInternational Adjudication, held by the Lecturer of the Masterclass. The Inaugural Lecture by Professor McLachlan will take place in the evening of 8 April 2027 at the offices of CMS Hasche Sigle in Frankfurt. Participants of the Masterclass are encouraged to participate in the Annual Lecture and make their travel arrangements accordingly.

Expressions of Interest
Prospective participants are invited to submit a short Expression of Interest setting out:

• their reasons for wishing to participate in the Masterclass;
• their particular interest in the subject matter addressed by the Masterclass;
• one or more specific questions, themes, cases, developments, or controversies arising from the Masterclass abstract that they would particularly like to discuss; and
• where relevant, how participation in the Masterclass relates to their current academic, professional, or research interests.

The Expression of Interest shall not exceed 500 words.

In addition to the Expression of Interest, applications must also include a short CV (2 pages max.).

Participation is open to advanced (Master level) students, PhD students and early Post-Docs(up to 2 years after PhD defence).

Selection
Participants will be selected on the basis of their demonstrated interest in the subject matter of the Masterclass, the quality of their Expressions of Interest, and the potential contribution of their proposed questions and perspectives to the discussion.

Applicants will be informed of the outcome of the selection process by 15 November 2026. Those selected will receive further information on exact times and locations of the Masterclass and the Annual International Adjudication Lecture, as well as suggestions for accommodation and travel to/from Mainz.

Stipends
One or two stipends between 500 and 1,000 Euro may be awarded to the applicant or two applicants whose Expressions(s) of Interest is judged to be particularly strong. The stipends are intended to support participation in the Masterclass by covering, or at least making a substantial contribution to, participation-related expenses. The stipends will be awarded on the basis of the Expressions of Interest, with particular attention to the applicant’s engagement with the subject of the Masterclass and the relevance and originality of the questions or topics proposed for discussion.

Submission
Applications should be submitted to Jan-Henrik Hinselmann (jhinselm@uni-mainz.de).

Deadline for applications is 31 October 2026.

For further information, please contact Jan-Henrik Hinselmann (jhinselm@uni-mainz.de).