World Series appeared in 9 and won 5. As of 2018, no team has won consecutive World Series championships since the New York Yankees in , , and —the longest such drought in Major League Baseball history. Until the formation of the American Association in 1882 as a second major league, the National Association of Professional Base Ball Players (1871–1875) and then the National League (founded 1876) represented the top level of organized baseball in the United States. All championships were awarded to the team with the best record at the end of the season, without a postseason series being played. From
Baseball World Cup the Amateur World Series, until the tournament in 1988. Until 1988, the Amateur World Series was held in intervals of one to four years, except for the eight-year period from 1953–61. From 1988 to 2001, the Baseball World Cup was held in intervals of two to four years. After 2001, the tournament was held every two years. Until 1998 the competition was limited to amateur players. After 1998, professional minor league players competed, but Major League Baseball did not allow its players to participate. In the months leading up to the high-profile first World Baseball Classic in 2006, many commentators