When pro baseball first "opened for business," the CPBL, which set the rules of the game, made it a point to limit the number of teams. They hoped to keep the number at six, until attendance grew to 80 % of capacity, after which other teams would be allowed in.
因此，訂定職棒遊戲規則的職棒聯盟，特別對參賽隊伍有所限制，希望維持現有的六個隊伍，等到票房成長到八成，再容納其他隊伍。