Kasumigaura is the Japan's second largest natural freshwater lake after Lake Biwa, and is located about 6090 kilometers northeast of Tokyo at the south part of Ibaraki Prefecture Kasumigaura was originally a bay and from the 10th to 15th century, sand carried by many rivers had been deposited, so it became a brackish lakeFreshwater pearls are produced by Hyriopsis cumingi (triangle shell) and Hyriopsis schlegeli (Biwa shell) commercially in China, and other bivalve mussels that live in lakes, riverbeds and creek bottoms in Japan (Biwa pearls and Lake Kasumigaura pearls), as well the United States (Mississippi River Basin)Lake Kasumigaura, located in the southeastern part of Ibaraki Prefecture, consists of three bodies of water, ie, Lake Kasumigaura (Lake Nishiura), Lake Kitaura, and the Hitachitone River Its surface area is about 2 ㎢, the second largest in Japan after Lake Biwa A total of 56 rivers, including the Sakura, inflow into the lake Pearl Wikiwand Lake kasumigaura pearls ...