'One Piece' Creator Submerges Secret Treasure Note to Mark 600 Million Copies Milestone

To celebrate surpassing 600 million copies sold, 'One Piece' creator Eiichiro Oda revealed the secret of the series' legendary treasure for the first time by writing it on paper. The note, split into two parts, includes a public question and a sealed answer placed inside a pressure-resistant glass sphere, which was submerged 651 meters underwater at an undisclosed location. The chest will remain underwater until the manga's final chapter is published. The project involved collaboration with Japan's marine science agency.