as possible to block the greatest area. Rules Infractions Infractions are generally punished by the loss of possession to the other team. Premature throw – Throwing the ball before the official has called 'play'. Ball over – The ball rebounds off a defending player, the crossbar or goalposts, and crosses back over half-court. Penalties A penalty throw may be awarded for: Ten second penalty – A team takes more than ten seconds to throw the ball back over the centre line. Delay of game – This can be caused by many different things. A coach reporting the wrong numbers for substitutions, a team not arriving in time for the coin toss that precedes the game, or too many or too few players taking the court. Illegal defence – This is called if a defender makes contact with the ball while no part of the body is touching the team area. Short ball – The ball fails to reach the opponent's team area when thrown. High ball – The ball does not touch the thrower's landing zone when thrown. Long ball – The ball does not touch the neutral zone when thrown. Eyeshades – Touching eyeshades without permission. Unsportsmanlike conduct – This can be a variety of things, from arguing with an official to pounding the floor and swearing Noise – Unnecessary noise by the offensive team that prevents the defence from tracking the ball while the ball is travelling down the court. Illegal coaching – Coaching from the bench during play or after an official has said 'Quiet please' with intentions of continuing or starting play. From 2006, rules allowed coaching from the bench during an official time-out. In a penalty situation, a single player is required to defend the entire goal for one throw. The player chosen is determined by the penalty. For instance, a high ball or illegal defence penalty is defended by the player who committed the penalty. On the other hand, an illegal coaching penalty is defended by a player chosen by the coach of the throwing team (previously the last recorded thrower of that team). Official rules The official rules for the sport are provided on the IBSA website. Rules may be adjusted every four years. Referees may be internationally certified under a structured scheme, from IBSA Goalball Level 1 to Level 3. Goalball world championships and Paralympic tournaments are called by Level 3 referees.