Oh Seung-hwan, the all-time saves leader in South Korean pro baseball with 277, completed his move to the Hanshin Tigers at a signing ceremony on Wednesday.
The 31-year-old right-hander, who has represented his country at the World Baseball Classic, joins the Tigers on a two-package contract worth an estimated ¥850 million.
Oh will wear the uniform with Kyuji Fujikawa's with old roster No. 22.
"I want to fulfill the role that (Hanshin) needs from me and aim for the championship," Oh, who said he had other offers, including from the major leagues, told a news conference.
"I am honored to be joining such a storied team. I will make a big effort to pitch great relief in Japan, too."
Hanshin general manager Katsuhiro Nakamura also attended the media event.
"I want (Oh) to be the major driving force that can help us win the league and the Japan Series," he said.
With ace reliever Fujikawa having moved to the Chicago Clubs, Hanshin pursued Oh to become the team's regular closer this past season.