Pearl Day

What Is Pearl Day?

Every July 11th is "Pearl Day" (真珠記念日, Shinju Kinenbi) in Japan. On July 11, 1893, during experiments at Shinmei-ura in Ago Bay (英虞湾, Ago-wan) and on Ojima island (now Mikimoto Pearl Island) in Mie Prefecture, Mikimoto Kōkichi (御木本幸吉, 1858–1954) found a semi-spherical pearl formed in an Akoya oyster — his first success in culturing pearls, showing that pearls could be grown through human intervention rather than found by chance in wild oysters. Mikimoto's achievement revolutionized the pearl industry globally, making cultured pearls accessible to the general public and establishing Japan as the world's pearl capital.

Mikimoto Kōkichi and Cultured Pearls

Mikimoto Kōkichi was the son of a noodle shop owner in Toba, Mie Prefecture, who became fascinated by the pearl diving (海女, ama) culture of the Ise-Shima region and determined to find a way to grow pearls artificially. Guided by zoologist Kakichi Mitsukuri and others, he began experiments in 1890, working for years with inserting nucleus material into Akoya oysters (アコヤ貝, Pinctada fucata) to stimulate pearl formation. After numerous failures, his July 1893 success produced a hemispherical cultured pearl — not yet the perfect round pearl he sought, but proof that the concept worked. He obtained a patent for semi-spherical pearls in 1896, and round cultured pearls were later achieved through research by Mikimoto and others, including his son-in-law Tokichi Nishikawa.

The Global Pearl Industry

Mikimoto's achievement democratized pearls — previously rare and extraordinarily expensive treasures obtained from wild oyster beds — by making them cultivatable in commercial quantities. Mikimoto pearls and the broader Japanese cultured pearl industry transformed the global jewelry market, making pearl necklaces and earrings accessible to middle-class consumers rather than only royalty and the very wealthy. Japan's Akoya cultured pearl remains the international standard for round cultured pearls, while Japan also produces freshwater, South Sea, and Tahitian cultured pearls.

Mikimoto's Legacy

Mikimoto Kōkichi lived to age 96, continuing to oversee his pearl empire until shortly before his death in 1954. Mikimoto Pearl Island (ミキモト真珠島) in Toba City, Mie Prefecture — one of the sites of his early experiments — is now a museum and tourist attraction celebrating the achievement that made Japan synonymous with pearl quality worldwide.

Fun Facts

• Ama divers: The female divers (海女, ama) of the Ise-Shima region once gathered wild pearl oysters as well as other seafood. Ama still dive in the region today, mainly for abalone and other shellfish, and Mikimoto Pearl Island holds ama diving demonstrations for visitors.
• Mikimoto's quote: When he met Emperor Meiji, Mikimoto is said to have declared that he would "adorn the necks of all the women in the world with pearls" — a democratic aspiration that his cultured pearl technology made surprisingly close to achievable.