Shinsuke J. Sugiyama

Shinsuke J. Sugiyama combined diplomatic work with a sustained interest in international law. He studied at Waseda and Oxford and entered Japan’s Foreign Ministry in 1977. His assignments included Washington, Seoul, and Cairo, while his work in Tokyo ranged from treaty affairs to development cooperation and climate negotiations. He led the Asian and Oceanian Affairs Bureau and served as vice minister before his appointment as ambassador to the United States in 2018. ¹

That legal background remained visible in his public diplomacy. At Yale in February 2020, Sugiyama explained Japanese policy through the 1956 Soviet–Japanese declaration and the U.S.–Japan security treaty. He argued that diplomatic legality needed to be joined to substantive justice, rather than reduced to procedural correctness. His academic work extended beyond occasional ambassadorial lectures: he taught international law at Waseda, wrote articles, edited books, and participated in the editing of a Japanese international law journal. ^{1, 2}