Slaughter rule

A slaughter rule, also well known by the slightly more polite term mercy rule or less commonly, knockout rule, brings a sports event to an early end when one team has a very large and presumably insurmountable lead over the other team. The winning team is said to be "slaughtering" the losing team. Slaughter rules are most common in games such as baseball or softball, where there is no game clock and play could theoretically continue forever.

Rules vary somewhat from one sports league to another. For example, in softball, the slaughter rule might be invoked if one team is winning by ten runs after five innings or fifteen runs after three innings.

The slaughter rule is used in amateur leagues, but seldom in professional leagues. It is common in video game simulations of sports because it helps move the game along.