With an area of 65.0 km² and a circumference is 114 km, Lake Hamana, near the southwestern end of Shizuoka Prefecture is Japan's tenth largest lake. It was a fresh-water lake until an earthquake in 1498 cut the sandbank that had closed it off from the Sea of Enshu.
A 16th-century tsunami opened the mouth of the lake further, and the result is a salt lake with an intricate shoreline that is a significant source of cultivated eels, oysters, nori and soft-shelled turtles along with wild caught sea bass, whiting, blowfish (fugu), pike, conger and flounder.
The region is also known for strawberries and mikan oranges.
The lake has developed as a resort area, with the major draw cards concentrated around Kanzanji-Onsen, a relatively new hot spring resort on the northeast of the lake with more than a dozen hotels and ryokans.
Most of the baths are found in hotels, and many are accessible to day trippers for a small fee. Kanzanji also attracts wind surfers, sea kayakers and parasailers in summer.
Since the Tokaido Shinkansen crosses the southern end of the lake, it is easily accessed from Tokyo, Nagoya and Osaka, but the fastest Nozomi do not stop in Hamamatsu.
Using the next fastest option (Hikari), it is around an hour and a half from Tokyo, slightly less from Osaka and roughly half an hour from Nagoya.
From Hamamatsu, it's a 40-minute bus ride to Kanzanji Onsen (frequent departures at least twice per hour), but the bus trip is not covered by the Japan Rail Pass.