A world region is a sub-agglomeration characterized by a significantly higher density of interactions within a broader, now global world system. Does East Asia—ranging from China, Korea, and Japan in the north to Indonesia in the south—represent such a world region? To answer the question regarding the regional character of East Asia, this comprehensive study reconstructs regional and global contexts in their historical depth. Since the stabilization of contacts in the early centuries of the Common Era, East Asia has experienced several waves of intensified economic, political, and cultural integration. Following a low point after World War II, decolonization, and independence wars, the opening and reform processes since the late 1970s have enabled the rapid re-integration of the region. This is examined in detail.