How has Japan dealt with the issue of information and chains of command in its disaster management system? In this essay, the authors provide a brief overview of the Japanese context and describe the firsthand experience of information flow and command structure in action in disaster medicine during the initial response for the Great East Japan Earthquake. Authors argue that while efforts have been made by scholars and practitioners to adapt the idea of the American Incident Command System into the Japanese system, the current structure based on ‘sectionalism’ stands as the major obstacle in developing a unified information and command system.