How Mikimoto Changed the Pearl Industry


Kokichi Mikimoto, the son of a noodle maker, had a dream and a hard-working wife, Ume. Together they set about to do what no one else had done—entice oysters to produce round pearls on demand. Mikimoto did not know that government biologist Tokichi Nishikawa and carpenter Tatsuhei Mise had each independently discovered the secret of pearl culturing—inserting a piece of oyster epithelial membrane (the lip of mantle tissue) with a nucleus of shell or metal into an oyster’s body or mantle causes the tissue to form a pearl sack. That sack then secretes nacre to coat the nucleus, thus creating a pearl.

Mise received a 1907 patent for his grafting needle. When Nishikawa applied for a patent for nucleating, he realized that he and Mise had discovered the same thing. In a compromise, the pair signed an agreement uniting their common discovery as the Mise-Nishikawa method, which remains the heart of pearl culturing. Mikimoto had received an 1896 patent for producing hemispherical pearls, or mabes, and a 1908 patent for culturing in mantle tissue. But he could not use the Mise-Nishikawa method without invalidating his own patents. So, he altered the patent application to cover a technique to make round pearls in mantle tissue, which was granted in 1916. With this technicality, Mikimoto began an unprecedented expansion, buying rights to the Mise-Niskikawa method and eclipsing those originators of cultured pearls, leaving their names only for history books.

Mikimoto’s efforts made pearls in a range of styles and prices available to consumers worldwide. Largely by trial and error over a number of years, Mikimoto did contribute one crucial discovery. Whereas Nishikawa nucleated with silver and gold beads, Mikimoto experimented with everything from glass to lead to clay to wood. He found he had the highest success rates when he inserted round nuclei cut from U.S. mussel shells. Although some countries continue to test other nuclei, U.S. mussel shells have been the basis for virtually all cultured saltwater pearls for 90 years.

Even though third with his patents and his secrets, Mikimoto revolutionized pearling. Ever the flamboyant showman and promoter, he badgered jewelers and governments to accept his cultured products as pearls. His workers created massive pearl structures, which he displayed at every major international exposition. By mastering the techniques, Mikimoto, then hundreds of other Japanese firms, made pearls available to virtually everyone in the world.