History of biwa pearl

Biwa pearl was first produced in the 1930s, their quality rivaled that of both natural and cultured seawater pearls, and they were far less expensive to own. Biwa pearls are some of the most famous freshwater pearls, created by the pearl mussels that live in Lake Biwa. Lake Biwa, near Japan's ancient capital of Kyoto, is traditionally the only place Biwa pearls is found. For many years any freshwater pearl was called a Biwa, regardless of its provenance.
The authentic biwa pearls are no longer created now. Kokichi Mikimoto is the man most credited with perfecting the techniques of freshwater pearl culturing. In the late 1900s, especially the 1970s, so many biwa pearls were harvested from the lake that pearl farmers managed to produce up to 6 tons of the pearls a year. This only lasted a short time before the biwa mussels became overharvested. Kokichi Mikimoto experimenting at Lake Biwa, seeded mussels only with soft mantle tissue. This resulted in an all-nacre pearl of good luster and unusual shape---the rice-grain shape was typical.
Today, the term "biwa pearl" can be used to describe several different types of pearls. Biwa's pearl production is negligible. China's huge natural and labor resources have put it at the forefront of cultured pearl production, and "Biwa" pearls sold from Japan today sometimes are produced in China. These are produced by introducing small amounts of mantle into the mussel. It should be noted, too, that biwa is sometimes used as a general term to describe these features.