The A's also have edges on the Giants in terms of overall postseason appearances (18-11), division titles (16-8) and World Series titles (4-3) since both teams moved to the Bay Area, even though the Giants franchise moved there a decade earlier than the A's did.
The City Series was the name of a series of baseball games played between the Athletics and the Philadelphia Phillies of the National League that ran from 1903 through 1955.