It's back today for its fourth season, and some teams are hoping they have finally gotten this interleague thing figured out.
If the Carp are to cast off the second-division citizenship they've held since 2002, Hiroshima will have to be much better against the Pacific League clubs than they were a year ago.
In 2007, the Carp posted Japan's worst interleague record, 5-18-1, so Hiroshima manager Marty Brown is eagerly looking forward to something better this year.
"It's not about last year, it's about this year," Brown said at Tokyo Dome on Sunday before his team lost 6-3 to the Yomiuri Giants.
Some of Hiroshima's troubles a year ago stemmed from the inability to adapt to unfamiliar pitchers. Tomonori Maeda, who reached the 2,000 hit mark during the summer, hit .153 off PL pitching.
"He's been playing forever and he's used to all the pitchers in this league. He knows how everyone pitches to him," Brown said of his 36-year-outfielder. "Against unfamiliar guys, he didn't know what to expect."
Brown believes the key is sticking with what works rather than trying to predict how the other guy will try to stick it to you.
He said the thought process should be: "OK, he's a left-hander or he's a right-hander, now go get him.
"You have to simplify the game, and last year I think we made it way too complicated.
"We have to stay with our strengths. Just because the teams are different, we can't go and change the way we play."
While the Carp enter interleague play in fifth place, the current Central and Pacific League leaders will also to drastically improve their interleague form if they are to finish first at season's end.
The CL-leading Hanshin Tigers had Japan's third worst interleague record a year ago (9-14-1), while the Saitama Seibu Lions (9-15) were the worst in the PL.
The Lions, who take a five-game lead over the Hokkaido Nippon Ham Fighters into interleague, will host the Tokyo Yakult Swallows starting Wednesday.
The Fighters, who won their second straight PL pennant last autumn after breaking Chiba Lotte's two-year lock on interleague titles, will be at Sapporo Dome tonight against the last-place Yokohama BayStars.
The fourth-place Yomiuri Giants, whose 15-9 record against PL clubs helped lift them to their first league title since 2002, will be in Chiba tonight to take on the Marines. Both clubs are badly in need of a fresh start after losing two out of three at home over the weekend to teams lower down in the standings.
Alex Ramirez, whose three-run homer helped ice Hiroshima on Sunday night, said he enjoyed interleague but would prefer to miss a few of the PL's pitching stars.
"[The Fighters' Yu] Darvish and [Tohoku Rakuten's Hisashi] Iwakuma, hopefully we can skip those guys," said Ramirez, whose club trails Hanshin by nine games.
The Tigers will be in Osaka tonight in the first leg of the Kansai derby against the cellar-dwelling Orix Buffaloes.
In tonight's other games, the CL's second-place Chunichi Dragons will be in Sendai, where the third-place Rakuten Golden Eagles are 16-6 this season.
The Carp, who have been on the road since May 5, are in Fukuoka to face the SoftBank Hawks.