Its deep blue color makes the Okinawa ocean, and popular as a souvenir, is a glass ball made with a hole made using a molding technique called burner work, just like dragonballs.The artisan melts colored glass one by one, rolled it into iron core, and layered with silver foil (ginpaku) in a special technique to create beautiful colors.There is no clear record of the type of dragonball that originated from Okinawa, which has been popular as a souvenir of Okinawa, but it is said to have been noticed since the late 80s and the color reminiscent of a deep sea has captured the hearts of visitors.