Over the years he has recounted these fragmented but vivid memories to school children, to journalists, to anyone seeking to document the trauma of the hibakusha, or the atom bomb survivors. These days, they are a small and dwindling group.
"There are only a few people like us who experienced the war and the atomic bombing. We are dying," Mr Mimaki says, while sitting in Hiroshima's Peace Memorial Park, where world leaders attending the G7 summit laid wreaths on Friday. "Sooner or later, there will not be a single hibakusha. How will Japan change by then?"