This long cultivation process makes South Sea pearls rarer — and more expensive. A single South Sea pearl can cost $1,500, and a necklace can reach over $200,000. So, how are these pearls grown?

According to Masanari Matsuda, 59, a curator at the Lake Biwa Museum, pearl cultivation began in the lake during the Showa Era (1926-1989), and the undertaking succeeded exactly 90 years ago.