Nowadays, we don’t know any better. A baseball game lasts nine innings. Except in Europe and during international tournaments where games can last only seven innings due to the mercy-rule (with a ten-run difference). But there was a time in which there was no rule that baseball games had to last nine innings. Read on and you will learn.
We all know that baseball wasn’t invented according to the myth that Abner Doubleday would be the spiritual father of the game we love so much. No the game evolved, likely from other games like rounders and stool ball, something yours truly has written about before.
As written in the prologue, we all know that a game has a minimum of nine innings, but there was a time when that wasn’t the case at all. Before the 1850s, there was no rule telling that a game should last nine innings. That rule was implemented in 1857 when a convention of baseball clubs in New York area decided that the game of baseball should last nine innings. The New York Knickerbockers, who organized the convention, wanted the game to last seven innings so they ended up at the “wrong” side of history.
But how many innings did a game last before that 1857 convention? That was depending on the score. The general rule was that the first team that scored twenty-one runs (called aces in those days) would win the game.
More rules were agreed on on that 1857 convention but more about that another time.
Source: Today in Baseball