One Piece, Japan’s popular pirate-themed manga series, finally has some real-life sunken treasure. Author Eiichiro Oda has apparently written the secret to One Piece on a piece of paper, which has been placed in a pressure-resistant glass sphere and submerged in the ocean. This is a publicity stunt to celebrate the long-running manga selling over 600 million copies worldwide, however the answer that fans have been waiting for won’t be revealed until the story’s climax.
The One Piece manga started in 1997. It follows the adventures of Monkey D. Luffy and his motley crew as they search for a legendary treasure called “One Piece," which was left behind by Pirate King Gol. D Roger. Since then it has spawned a highly popular multimedia franchise of anime series, movies, and games. But what exactly One Piece is has remained a secret.
However, this week Oda has literally turned the ultimate goal of his 28-year-old series into pirate booty. With the help of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Oda has submerged the secret to One Piece at an undisclosed location 651 meters below sea level, as reported by The Sankei Shimbun.
As a teaser, a mock-up of half of the piece of paper has been printed in the March 4 morning editions of Japan's Asahi Shimbun and Yomiuri Shimbun newspapers. Fans are urged to keep the mock-up until the secret is revealed.
3月4日(水)付
朝日新聞 朝刊
読売新聞 朝刊
に尾田先生が秘密を書き記した
原寸の紙片が掲載されています。
真実が記された紙片は、
物語の完結後に公開を予定。すべてが明らかになるその日まで、
こちらをぜひお手元に。#ONEPIECE #ONEPIECE6億部 pic.twitter.com/5baGaSnsEL— ONE PIECE スタッフ【公式】/ Official (@Eiichiro_Staff) March 4, 2026
The teaser doesn’t reveal anything juicy though. The mock-up just says, “One Piece is… and… Monkey D. Luffy is…” Talk about cryptic! There’s also a dramatic documentary-style video of the treasure being submerged on One Piece’s official YouTube.
Over on social media, people are joking that some One Piece fans are diehard enough to actually try to find the treasure in real life. One commenter quipped in Japanese, “What if this marks the dawn of The Great Pirate Era in our modern times?,” referencing the time period from One Piece. Some fans have already started the detective work, with one Redditor proposing that the secret to One Piece could be lying somewhere on the seabed of Suruga Bay, off Japan’s Shizuoka Prefecture.
Oda will reveal what is on the paper in One Piece's final chapter, and there are plans to retrieve the glass sphere from the ocean then. However, there is still no official timeline for when the series will end. Perhaps this teaser suggests that we can expect the answer to what One Piece actually is sooner rather than later.
Verity Townsend is a Japan-based freelance writer who previously served as editor, contributor and translator for the game news site Automaton West. She has also written about Japanese culture and movies for various publications.
