The calculated distance (air line) between Ōkuchi-shinohara and Kitakyushu is approximately 124 miles respectively 199 kilometers.
By car or train, the actual journey to Kitakyushu is certainly longer, as only the direct route (as the crow flies) between Ōkuchi-shinohara and Kitakyushu has been calculated here.
Air line (approximately)
199 kilometers
108 nautical miles