The calculated distance (air line) between Shizuoka and Hitachi-Naka is approximately 155 miles respectively 250 kilometers.
By car or train, the actual journey to Hitachi-Naka is certainly longer, as only the direct route (as the crow flies) between Shizuoka and Hitachi-Naka has been calculated here.
Air line (approximately)
250 kilometers
135 nautical miles