The calculated distance (air line) between Ōyama and Higashi-ōsaka is approximately 150 miles respectively 241 kilometers.
By car or train, the actual journey to Higashi-ōsaka is certainly longer, as only the direct route (as the crow flies) between Ōyama and Higashi-ōsaka has been calculated here.
Air line (approximately)
241 kilometers
130 nautical miles