Education: PhD in International Relations, London School of Economics and Political Science (LSE), University of London, UK (1998), MA in Political Science, Waseda University, Japan (1993), BA, Waseda University, Japan (1991). 

Professional Positions) After working as a part-time teacher at LSE and Keele University, he took a research fellow position at the Institute for Peace Science of Hiroshima University, where he became Associate Professor. Then, he took the current position at the Tokyo University of Foreign Studies in 2013. He has been a visiting scholar at the Lauterpacht Research Centre for International Law, Cambridge University (2000) and at the Center for the Study of Human Rights, Columbia University (2002). He was Visiting Professional at the International Criminal Court (2017).

Publications) He is the author of many books and articles including Partnership Peace Operations: UN and Regional Organizations in Multiple Layers of International Security (Routledge, 2024). He has received academic awards including Osaragi Jiro Rondan Award of Asahi Newspaper (2003), Suntory Academic Award (2012), Yomiuri Yoshino Sakuzo Award of Yomiuri Newspaper (2017).