ASA Official Softball Rules

These are the basic rules set forth by the Amateur Softball Association of America, which governs more than 3.5 million players.

The playing field

The field of play varies from adult to youth. The adult leagues are broken down into fast pitch, modified pitch and slow pitch.
For fast pitch, bases are to be 60 feet apart, the pitcher's mound (which will contain a rubber or wood plate), measuring 24 inches long and six inches wide. It is to be 46 inches away from the plate for men, and 43 inches away for women. The minimum fence is to be no less than 200 feet away from home plate for women--225 feet for men--with the maximum being no greater than 250 feet for both men and women.
For the modified division, the bases are 60 feet apart, with the pitching mound 40 feet away from the plate for women; the distance is 46 feet for men. The maximum fence distance is 200 feet away from home plate for women and 265 feet for men. No distance greater than 300 feet is allowed.
For slow pitch, the bases are 65 feet apart for both men and women. The pitching mound should be 50 feet from home. The minimum fence distances from home: 265 feet for women, 300 for men and 275 for co-ed leagues. The maximum fence distances from home are 275 feet for women, 315 feet for men and 300 feet for co-ed.
For youth leagues 18 years and under, fast-pitch leagues all play with bases 60 feet apart. The pitching mounds vary from 35 inches to 46 inches, depending on age.The minimum fence ranges from 150 feet to 225 feet away from home, with the maximum fence distance ranging from 175 to 250 feet.
For youth leagues 18 years and under, slow-pitch leagues have the bases 65 feet apart, with pitching mounds ranging from 40 to 50 feet from home plate. The minimum fence ranges from 175 feet to 275 feet away from home, with the maximum ranging from 200 to 300 feet.

Equipment

Bats can be either aluminum or wood, but cannot be longer than 34 inches or weigh more than 38 ounces.
There are five types of softball approved by the ASA--the 10-inch, 11-inch, 12-inch, 14-inch and 16-inch softball--all of which should be covered by a leather or synthetic material.
All adult fast-pitch, modified and junior Olympic players must wear double-eared helmets while batting. Uniforms are to be consistent on every team and hats are mandatory while in the field for fast-pitch male players, while they are optional for females.

Players and coaches

Nine players are required for fast pitch and modified pitch, which includes a pitcher, catcher, first baseman, second baseman, third baseman, shortstop, left fielder, center fielder and right fielder. The team can also include a designated hitter in 10-player leagues.
Ten players are required on the field for slow pitch, which includes an extra fielder. Ten players are also necessary for co-ed slow pitch, with five males and five females. Any player may be replaced by a substitute, and may re-enter the game just one time after that.
Each team must have a coach that is aptly dressed in a team uniform and is responsible for presenting a lineup and roster changes during the game. They are responsible for the actions of their team and are not allowed on the field to coach their team. They must stay in the bench area or dugout. Each team can also have a first base coach and a third base coach.

Game play

Each game consists of seven full innings, unless the second team to bat (home team) scores more runs than the other team through six and a half innings. A game will also be called if one team is ahead by 15 runs after three innings or eight runs after five innings (fast pitch), 10 runs after five innings (modified), 20 after four innings or 12 after five (slow pitch). If a game is tied after seven innings, it will go into extra innings.

Pitching rules

A pitcher must make two full underhand rotations and deliver the ball to the plate with one foot on the pitcher's plate and one foot stepping forward in fast pitch. The motion must be an underhanded, with the palm of the throwing hand either up or down, in modified or slow pitch.