Softball is a team game enjoyed by many in the United States and countries around the world. The game has no clock, and play could theoretically continue forever, so the mercy rule (aka slaughter rule) is invoked when one team has a presumably insurmountable lead over another, bringing the lopsided game to an end. It’s called the mercy rule because it spares the losing team any further humiliation. Mercy rules only apply to the score of a game.
ASA Mercy Rule
According to the Amateur Softball Association of America (ASA) rules, a lopsided game is called after five innings (4 1/2 innings if the home team is winning). There is one rule for regular season games and another one for the playoffs.
ASA Regular Season/Playoffs
Under ASA rules, a regular season game is called when a team is up 12 runs or more after five innings (4 1/2 innings if the home team is ahead). A playoff game is called when a team is up 15 runs or more after five innings.
ISF Mercy Rule
According to the International Softball Federation (ISF) rules, a game is called after three, four, or five innings depending on the score. The rules slightly differ between slow-pitch (SP) and fast-pitch (FP) games.
ISF FP/SP Mercy Rule
Under ISF rules, a fast-pitch game is called when a team is up 15 runs after three innings; 10 runs after four innings or seven runs after five innings. A slow-pitch game is called when a team is up 20 runs after four innings or 15 runs after five innings.