The calculated distance (air line) between Hamamatsu and Ōmihachiman is approximately 97 miles respectively 157 kilometers.
By car or train, the actual journey to Ōmihachiman is certainly longer, as only the direct route (as the crow flies) between Hamamatsu and Ōmihachiman has been calculated here.
Air line (approximately)
157 kilometers
84 nautical miles