The popular manga series “One Piece” was officially recognized by Guinness World Records on Monday as the comic book series with the most copies published by a single author.

Shueisha Inc. had published more than 320 million copies of Eiichiro Oda’s series in 77 volumes as of the end of last year.

The series began in the publisher’s Weekly Shonen Jump magazine in 1997.

At a ceremony in Tokyo, Yoshihisa Heishi, the magazine’s editor-in-chief, received the Guinness certificate on behalf of Oda.

“I am happy that ‘One Piece’ has become (famous) worldwide,” Heishi said.

In a statement, the cartoonist said he hopes to continue producing work that matches the significance of the world record.

The cartoon’s story centers on Monkey D. Luffy, who dreams of being the king of pirates as he travels the seas with his buddies in search of a treasure called One Piece.

“One Piece,” which started out in 1996, has been one of the most popular and financially successful manga in the Japanese market.