To date, Eiichiro Oda’s One Piece manga series has sold over 300 Million copies in print since it’s debut in 1997, which is the most ever in Shonen Jump history. What’s more astonishing, in the past few years since 2009, One Piece manga has had over 130 million copies sold!
In 2013, over 17 million copies of One Piece have flown off the shelves, with One Piece Manga 72 and One Piece Manga Volume 71 (the latest volumes) both contributing 1.5 million a piece (for 3 million total) in their first three days of their launch at Japanese retailers.
Shueisha, the company behind One Piece, has launched special campaign called Sanoku ThanX (“300 million thanks”) in which they run special ads run in almost every major Japanese newspaper to celebrate the accomplishment. You can see some of the ads at Shueisha’s website