Abstract
Pacific league teams have been the champion teams in the NPB for the recent eight years, and ability differences among the relievers in both leagues have been noted. Major determinants of team wins during the regular season might be different between both league teams. To explore the determinants of win rate in each league, the current study analyzed team stats. Two major findings associated with baseball stadium size were found. First, central league teams can offset poor pitching performance by batting, although the effect of good pitching on team wins among central league teams is smaller, compared to that of pacific league teams. Second, increasing the number of stolen bases per game does not have a significant effect on team wins. Pitchers in the central league teams should improve pitch mix to reduce the number of home runs allowed per game.
