true even on the rare occasion when a game is played at a ballpark not home to either team.) Occasionally, the advance schedule is subsequently altered due to a game postponement or a one-game tie-breaker to determine which team will play in the postseason. Before 2013, the schedule included 252 "interleague games" that matched one team from the American League and one from the National League; the other 2178 games matched a pair from within one league. About half of the latter matched teams from within one division and about half matched teams from different divisions in one league. In the Central Division of the National League, which alone had six teams, every pair of division rivals played 15 or 16 games. Within the other, smaller divisions every pair of teams played 18 or 19 games. These interleague games were played from mid-to-late May to late June or early July. Division games (1091). There are 61 pairs of teams from within one division. 25 pairings will play 19 games each (475 games) 21 pairings will play 18 games each (378 games) 13 pairings will play 16 games each (208 games) – most NL Central pairings 2 pairings will play 15 games each (30 games) – two NL Central pairings Total: 1091 games. Other intraleague games (1087). There are 150 pairs of teams from two different divisions within one league. 23 pairings will play 10 games each (230 games) 15 pairings will play 9 games each (135 games) 8 pairings will play 8 games each (64 games) 34 pairings will play 7 games each (238 games) 70 pairings will play 6 games each (420 games) Total: 1087 games. Interleague play The schedule for interleague play comprised 84 three-game series in each season from 1998 to 2012, divided as six series (18 games) for each of fourteen AL teams and as many as six for each of sixteen NL teams. Among the 224 interleague pairs of teams, 11 played six games every year, which were scheduled in two three-game series "home and home", or one at each home ballpark. Five of these 11 special arrangements matched two teams in the same city or in neighboring cities, where they wholly or partly share territorial rights. Six were regional matches at greater distance, four of which were in the same state. Baltimore vs. Washington Chicago Cubs (North Side) vs. Chicago White Sox (South Side)