Climax Series

The Climax Series (クライマックスシリーズ, Kuraimakkusu Shirīzu^?) is the annual playoff system employed by Japan's Nippon Professional Baseball (NPB). It determines which two teams from the Central League (CL) and the Pacific League (PL) will compete in the Japan Series for the national championship. Since the creation of the NPB's two-league system in 1950, the leagues have used several different methods to determine entry to the Japan Series. The current system has been used since the 2007 season.

Both leagues play a 144-game regular season, after which the top three teams in each league compete against one another in a two-stage playoff. In Stage 1, the teams that finish the regular season with the second- and third-best records play one another in a best-of-three series. The winners of these three-game series advance to Stage 2 to face each league's regular-season champion in a six-game series, which the regular-season champion starts with a one-game advantage. The winners of each league's Stage 2 series compete against one another in that year's Japan Series.

Since the creation of the NPB's two-league system, the regular-season winner of the CL had always advanced to the Japan Series, where it competed against the PL champion. The PL used the same system until 1973, when the league created NPB's only postseason play prior to 2004 (other than the Japan Series). This system matched the team with the best first-half record against the team with the best second-half record. The winner of this best-of-five series advanced to the Japan Series, where they played against the CL champion. This system proved problematic when the Hankyu Braves won both the first and second halves of the 1976 and 1978 seasons, making a playoff series unnecessary. The system was eliminated after the 1982 season. Instead, the PL announced the following season that the first- and second-place teams would compete in a best-of-five playoff series after the 130-game regular season if five or fewer games separated the two teams. Unpopular with most baseball media and fans, the idea was scrapped after three seasons with a series never needing to be played. The two leagues returned to sending the team with the best regular season record in their respective league to compete against each other in the championship series.

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