The calculated distance (air line) between Hamamatsu and Yotsukaidō is approximately 152 miles respectively 245 kilometers.
By car or train, the actual journey to Yotsukaidō is certainly longer, as only the direct route (as the crow flies) between Hamamatsu and Yotsukaidō has been calculated here.
Air line (approximately)
245 kilometers
132 nautical miles