How to study regionalism in Greater East Asia For a long time, East Asia’s regional institutional environment was based on comparison with the European case What is Regionalism? On the Concept of region, regionalism and regionalization “Katzenstein defines regions as having both “material and symbolic dimensions” that are traceable in “patterns of behavioral interdependence and political practice.”3 In other words, regions “reflect the power and purpose of states.”4 This emphasizes the importance