Home Plate Umpire
Umpires working home plate in a softball game have the most responsibility of any umpire on the field. They must call every pitch a ball, strike or foul within a strike zone which varies from batter to batter. This requires the umpire to pay close attention to each pitch and the number of balls and strikes with each batter, as well as how the pitcher pitches the ball and whether he is doing it legally or not. They must also pay attention to other rules pertaining to batters and catchers, for example, making sure batters stay within the batter's box when they are hitting, catchers don't interfere with a batter's swing and batters don't interfere with a catcher trying to throw base runners out. The home plate umpire must also call base runners out or safe at home plate, which are also often game-deciding calls.
Umpires are also assigned to watch each base, from first to third. These umpires have a number of duties each inning, which entail watching each base and deciding whether runners are safe or out on plays at that base. First base umpires usually have the most challenging job of the three, as many close plays are made at first base. They must watch the base to see if the runner beat an attempted out and is safe, or if the throw beat them and they are out. These umpires must also watch baserunners who are stealing bases and determine if they were tagged out, picked off, or if they made it to the bag before the tag was made. These umpires must also watch the pitcher, to see if they are pitching illegally.
While these umpires are not always needed in smaller league games, they are often hired to simply watch balls hit down the lines of the outfield and decide whether the ball is fair or foul. If the ball lands on or inside the white line, it is fair. If it lands outside the white line, it is foul. These umpires also have the final call on whether home runs bounced off the top of the wall are fair or not.