The World Series is the annual championship series of North American-based Major League Baseball (MLB), played since 1903 between the American League (AL) champion team and the National League (NL) champion. Prior to 1969, the top-ranked team in each league automatically advanced to the World Series; since then each league has conducted a championship series (ALCS and NLCS) held shortly before the World Series to determine which teams will advance. 109 Series have been contested, with the AL winning 63 and the NL winning 46. The winner of the World Series championship is determined through a best-of-seven playoff and the winning team is awarded the Commissioner's Trophy. As the series is played in October, which is one of the fall (autumn) months in North America, it is often referred to as the Fall Classic.
The most recent World Series was won by the Boston Red Sox, who defeated the St. Louis Cardinals four games to two in 2013. In the American League, the New York Yankees have played in 40 World Series and won 27, the Philadelphia/Oakland Athletics have played in 14 and won 9, and the Boston Red Sox have played in 12 and won 8, including the first World Series. In the National League, the St. Louis Cardinals have appeared in 19 and won 11, the New York/San Francisco Giants have played in 19 World Series and won 7, and the Brooklyn/Los Angeles Dodgers have appeared in 18 and won 6.