From 2013, the USA-led alliance triangle with Japan and South Korea has defied expectations. Drawing together articles commissioned from leading experts in all three countries by the new online journal The Asan Forum, this book reconsiders what we thought we knew about the three legs of this triangle. Varied chapters cover the USA-South Korea alliance at 60 years, Japan-South Korea relations under stress, Japan's national security policy, United States relations with both allies, and Japanese and Korean national identities. A picture emerges of two strong United States alliances increasingly at odds with each other, and of Japan-South Korea relations newly troubled not only by intensifying national identities but also by divergent strategic calculations. This volume shows how vital this triangle is to understanding USA policy in Asia by bringing to light the dynamics of triangularity in the shadow of China's rise and the North Korean threat.