The calculated distance (air line) between Hiroshima and Higashi-ōsaka is approximately 179 miles respectively 289 kilometers.
By car or train, the actual journey to Higashi-ōsaka is certainly longer, as only the direct route (as the crow flies) between Hiroshima and Higashi-ōsaka has been calculated here.
Air line (approximately)
289 kilometers
156 nautical miles