Seasonal vegetables, fine food, and lake activities Hamamatsu and Lake Hamana, a lakeside community at an ancient crossroads Lake Hamana (Hamanako) is a lagoon connected to the ocean near the geographical center of Japan. Although originally a lake, more than five hundred years ago an earthquake connected the lagoon to the sea, turning the water brackish (slightly salty). For over a century, Lake Hamana has been a prime location for cultivating eels, soft-shell turtles, seaweed, and oysters. The Hamamatsu and Lake Hamana area is known for its unique fishing methods and fresh seafood.