Adachi offers a groundbreaking reinterpretation of international relations through a non-Western lens and explores how Japan strategically engaged with, resisted, and at times created international systems—from the Chinese tributary system to the Western sovereign state system. By highlighting Japan’s fluid participation in overlapping orders, the book challenges the notion of a singular, Western-centered international system. It blends global history with international relations theory to examine how identity, rather than mere power or interest, shapes a state’s stance toward international systems to allow readers to gain a richly textured understanding of global politics, informed by historical sources from across Asia and Europe, and a fresh analytical framework for interpreting today’s multipolar world. A valuable resource for scholars, researchers, and professionals of International Relations, Global IR, Asian history, and diplomatic studies and those interested in the evolution of international systems, the dynamics of U.S.-China rivalry, and the role of non-Western actors in shaping global order.