This is a basic explaination of the rules of field hockey as well as the types of fouls and the penalties involved.
Field hockey is a game in which two teams attempt to score a goal by using sticks that are curved at one end. Each team is comprised of 11 players, usually 5 forwards, 3 halfbacks, 2 fullbacks, and 1 goalkeeper and 5 substitutes. A match between two teams consists of two halves, each 30-35 minutes in duration. At halftime the teams take a short break before changing direction and defending the opposite end. Field hockey is usually played outdoors on grass or an artificial turf field. The field is 100 yards long and between 55 and 60 yards wide.
Play begins from the center spot; a coin deciding which team has first hit. One player from the team that wins the toss starts the game by hitting the ball into play with a pass to a teammate. This procedure is repeated to reactivate the ball by the team scored against, when a goal is scored, and when play begins again after halftime. If there is a stop in action, the re-start is called a Bully. This is when the ball is placed on the ground between two players, one from each team. The players tap the ground with their sticks once, then tap their sticks together three times before going for the ball. The other players must be at least 5 yards from the ball during a Bully.
The ball is moved toward the goal by use of the stick, using only the flat left-hand side. Players make advances towards the opposition's goal by either dribbling, pushing the ball along or by passing to a teammate. They will either take the ball on or pass to another teammate until they reach the striking circle. This is the zone in front of the goal that is a semicircle with a radius of 16 yards, affectionately nicknamed the "D". All goals have to be scored from inside this space.
Goals are scored when the ball passes over the goal line between the two goal posts. These are centrally positioned on each end line. For the goal to count, however, the ball must either be struck by a player inside the striking circle or touch the stick of an attacking player, standing inside the striking circle, before crossing the line.
If play becomes too intense, fouls or infractions become more common. The infraction that is made most often is obstruction. This is called when a player deliberately blocks an opposing player from reaching a ball while not trying to play it themselves. No player, except for the goalkeeper, is allowed to touch the ball with any part of their bodies during play. Hitting the ball with anything other than the flat side of the stick is also considered an infraction. Last but certainly not least is dangerous play. This is not specifically defined, but is based on the judgment of the officials. It is usually called when the ball comes above the knees of nearby players or when a high ball goes into a crowd of players. A foul is also committed if the stick is used in a dangerous manner. Officials may award a free hit, a penalty corner, or a penalty stroke to the offended team. A free hit means that the offended player gets possession of the ball with defenders at least five yards away. This is awarded for any minor fouls occurring outside the circle.
In a penalty corner, the ball is placed on the goal line at least 10 yards from the nearest goal post. One attacking player hits the ball to a teammate just outside the striking circle line. No shot on goal may be taken until the ball is stopped outside the circle. All attackers must be outside the circle before the shot is taken. On defense, a maximum of five defenders may be behind the goal line while the remaining defenders must be positioned beyond the centerline. Penalty corners are awarded for any infraction within the striking circle or when a defender intentionally sends the ball into touch beyond the goal line.
A penalty stroke is one-on-one between an offensive player seven yards in front of the goal vs. a goalkeeper on the goal line. All other players must stand behind the 25-yard line. The goalkeeper must stand with both feet on the goal line and may not move either foot until the ball has been played. A penalty stroke is awarded when an infraction by a defender prevents what would have been a certain goal, or for an intentional foul by a defender within the striking circle.
Because this game is more a defensive game than an offensive game goals tend to be infrequent. Rules regarding overtime vary depending on the leagues.