The invasion of Ukraine by the Russian Federation and the subsequent military campaigns entail several classical aspects of armed conflict. First, it is a type of international armed conflict between two sovereign states that had been prevalent until the middle of the twentieth century but not in the last several decades. It is also a direct intervention by a superpower into a neighboring state with the former's aspiration of territorial expansion. This action evokes a scheme of war reminiscent of the nineteenth or early twentieth century. At the same time, however, the invasion is generating in the international community a sense of new phenomena, leading to a new era that may be different from the past three decades following the end of the Cold War. In fact, the hostilities between the Russian Federation and Ukraine, as well as reactions by other states and international organizations, have raised legal and political issues that require scholars to reexamine existing frameworks of the international community and individual rules of international law. The process of applying international law to states is a dynamic one. Rules of international law may and should regulate the behavior of states and provide standards to decide whether a particular act by a state is permissible. At the same time, however, states may change or replace existing rules, and a significant event or series of such events may be a strong motivator to create a new legal framework. In this regard, rules of international law and the conduct of states are in a dialectical relationship. International law can both shape a mode of conduct and be shaped by that conduct-being its creator as well as its creation. The Ukraine conflict is not an exception. We can discuss the conduct of the Russian Federation, Ukraine, other states and international organizations and evaluate their legality and legitimacy from the viewpoint of existing rules. However, we may also reevaluate the current rules of international law through the lens of the Ukraine conflict and discuss possible changes to those rules in the future. Inspired by the latter aspect of the international legal process, the present book aims to examine the impact of the Ukraine conflict, whether salient or potential, on various rules of international law. Most of the authors are from Japan and other Asian countries that are geographically remote from the site of the conflict. It is often true, however - and particularly in this case - that those keeping an appropriate distance can look at relevant issues in a broader view and from a more objective perspective. To what extent and in what manner may the Ukraine conflict have an impact on the legal framework of the international community and the rules of international law? This book is the first to answer those questions in a comprehensive manner.

Shuichi Furuya is a professor of international law at Waseda Law School, Tokyo. He was a member of the UN Human Rights Committee (2019-2022, Vice-Chair 2021-2022), a member of the International Humanitarian Fact-Finding Commission (2012-2021, Vice-President 2015-16), Co-Rapporteur of the ILA Committee on Reparation for Victims of Armed Conflict (2004-2014), and the editor-in-chief of Journal of International Law and Diplomacy (2014-2016). Hitomi Takemura has been a professor of international law at the Graduate School of Law and the Graduate School of International and Public Policy (IPP) of Hitotsubashi University, Tokyo, Japan. She lectures international law in Japan since 2008 and specializes international criminal law. She earned an LL.M. in international law from Hitotsubashi University, an LL.M. in public international law and international criminal law from Leiden University, and a PhD in law from the Irish Centre for Human Rights at the National University of Ireland, Galway in 2008. Her publications in English include the Rohingya Crisis and the International Criminal Court (Springer, 2023) and International Human Right to Conscientious Objection to Military Service and Individual Duties to Disobey Manifestly Illegal Orders (Springer, 2008). Kuniko Ozaki is Professor of International Law at Chuo University, Faculty of Law. She served as a judge of International Criminal Court between 2010 and 2019. She was a Second Vice-President of the Court between 2015 and 2018. During her tenure, she sat on various cases including Bemba, Kenyatta (Presiding) and Ntaganda cases. Professor Ozaki graduated from Tokyo University in 1978 and obtained an M. Phil. in International Relations at Oxford University in 1982. Afterwards, she worked in several positions for the Japanese Foreign Ministry and Justice Ministry. From 2006 to 2009, she worked for the United Nations Office on Drugs and Crime where she was Director for Treaty Affairs. She has also worked as a professor of international law at Tohoku University Graduate School of Law and at other universities and has written extensively on international criminal law, refugee law and law of human rights.