The Michigan High School Athletic Association, or MHSAA, has established softball rules that all Michigan high schools must follow. Those rules include field distances, pitching distances, number of players and equipment. The rules are in accordance with the United States Specialty Sports Association softball rules.
The Softball Field
The pitcher's mound is 43 feet from home plate and all pitchers must begin their delivery from the pitching rubber. All bases should be 60 feet apart. All fields that have fences for home runs must set the fences between 200 and 225 feet from home plate. All bases are 15 inches square, and a double base is used at first base for the safety of the players.
All batters and runners must wear helmets with face masks at all times. Chin straps are optional on those helmets. Catchers must wear catcher's masks, chest protectors and shin guards. The catching mask must have a throat protector attached to the bottom rung, unless the catcher is using a hockey-style goalie mask. In that case, a throat protector is not needed. Bats cannot be longer than 34 inches, and the barrel may not be more than 2 1/4 inches in diameter at its widest. The bat cannot exceed 31 1/2 ounces.
All games are seven innings long. If a team is ahead by 12 runs after three innings, the surrender rule is invoked. The surrender rule is also invoked if a team is ahead by 10 runs after four innings or eight runs after five innings. Nine defensive players can be on the field at any one time, but the batting team may use 10 batters if it chooses. The batting team can use a designated hitter to bat for any defensive player (not just the pitcher) and an additional batter in the lineup as well.