The calculated distance (air line) between Narutochō-mitsuishi and Kainan is approximately 35 miles respectively 56 kilometers.
By car or train, the actual journey to Kainan is certainly longer, as only the direct route (as the crow flies) between Narutochō-mitsuishi and Kainan has been calculated here.
Air line (approximately)
56 kilometers
30 nautical miles