Not that we necessarily required an further evidence of the popularity of One Piece, but now comes word that with the release of its 74th volume, Eiichiro Oda's pirate manga has sold more than 310 million copies in Japan alone.

It's worth noting that it was only November when Shueisha Inc. and Viz Media took out newspaper ads trumpeting the 300-million copy milestone (with another 45 million outside of Japan). Earlier that same month, it was revealed that One Piece has sold 130.15 million copies in Japan just since 2009, the year that market research firm Oricon began reporting book sales.

So what's the secret behind the success of the world's bestselling manga? Its sometimes-manic mix of action, comedy and sorrow, a seemingly magic formula the 39-year-old Oda attributes his short attention span. "The thing is, I get bored easily,” he told The Japan Times last fall. “So if my manga was just about the action, or comedy, or tear-jerking moments, I would get bored. I change the style of the series to keep up my motivation to draw. [...] Humans can only come up with new ideas when they’ve reached their limits. When I finish a manuscript, I am completely exhausted.”

Oda, who's been drawing One Piece since 1997, just announced that he's placing the manga on hiatus for two weeks while he has his tonsils removed. "Since I'm having this surgery anyways, I plan to have a bazooka installed on my shoulder," he said in a message to fans. "I'll be back with my body stronger, so I can clear my workload in the latter half of this year. I'll be right back, so please come play with me again."

(via Japanator)