The calculated distance (air line) between Kitakyushu and Chikushino-shi is approximately 31 miles respectively 50 kilometers.
By car or train, the actual journey to Chikushino-shi is certainly longer, as only the direct route (as the crow flies) between Kitakyushu and Chikushino-shi has been calculated here.
Air line (approximately)
50 kilometers
27 nautical miles