This paper contributes to the conceptual and empirical development of 'preparedness pedagogy'. Preparedness involves learning, thus disaster risk reduction (DRR) should be discussed more in the field of education, particularly its sub-discipline of public pedagogy. Disaster risk reduction education should have an element of "a pedagogy in the interest of publicness," which is an experimental pedagogy in which citizens act in togetherness to develop their own preparedness. The paper pays attention to the two phrases utilised in the recent DRR discourse -- 'integrated' DRR and 'participation by all' -- and examines the case of Japan, applying whole-system thinking. It is suggested that 'the mesosystem' of the DRR system yields relationships and learning, and thus enables collaboration, change and 'participation by all'. Preparedness pedagogy has a role to play in this. The mesosystem functions as the confluence between state-led and community-based DRR to truly integrate the system.