Before the game begins, the umpires check every stick for legality. The most common illegality in a stick is that its pocket is too deep. The strings at the bottom of the stick's head can be pulled to tighten the pocket.
If a player commits a foul, the umpire blows the whistle and play stops. The player fouled wins or retains the ball, while the player who fouled her is moved several yards behind or to the side of the player she fouled.
If a major foul is committed in the arc by the defense, the umpire blows the whistle, and a "free shot" on goal is taken by the player fouled. All of the defense players are required to clear the arc to the border closest to which they were standing when the whistle blew. The attack player who was fouled takes her place at the hash mark closest to which she was standing when she was fouled. The defense must move away at least four meters from the fouled player. When the umpire blows the whistle again, the player can take a shot on goal or pass while the defense moves in.
When the umpire blows the whistle because a foul has occurred, or the ball has gone "out of bounds" all players must stop and check all forward movement. Play resumes and the players can move when the umpire blows the whistle again.
Checking -- the method by which a player knocks the ball from another's stick -- is prohibited when it is: directed toward the face; uncontrolled; holding down the other's stick,or when the checker's stick is too close to the head or face.
Defensemen may not remain in the arc without guarding another player for more than three seconds.
When the ball is grounded, covering it with the back of a stick's net, and preventing play by another player is prohibited.
No players, other than the goalie, may enter the circle around the goal cage if the goalie is present.