The calculated distance (air line) between Kumamoto and Imarichō-kō is approximately 57 miles respectively 92 kilometers.
By car or train, the actual journey to Imarichō-kō is certainly longer, as only the direct route (as the crow flies) between Kumamoto and Imarichō-kō has been calculated here.
Air line (approximately)
92 kilometers
50 nautical miles