OFFSIDE POSITION
Offside position occurs when a player is nearer the opponents' goal line than the last two opponents and is ahead of the ball. Measure relative position by players' torsos, not their arms or legs. No part of the attacking player, except their arms, may be nearer the opponents' goal line than that of the second-last defender. The easiest way to remember this position is to remember that no part of the attacker that can legally play the ball (i.e., head, leg, torso) may be ahead of the ball and the second-to-last defender. It is not necessary to "see daylight" between them for one to be considered nearer than the other. Here are two examples:

JUDGMENT OF OFFSIDE POSITION
The referee must judge offside position only when the ball is played by a teammate of the attacking team. The referee's decision to penalize the player for being in that position can be made at the moment the offside position is judged if the other requirements of Law XI are met, but it can also be made at any time from that point forward until a new action on the field puts the attacker "on-side". The condition of being in an offside position (and the possibility of being penalized) continues no matter where that player may move, no matter where the ball may move, and no matter where the defenders may move.

It is not an offside offense to be in an offside position; it is an offense to interfere with play or with an opponent or to gain an advantage when in such a position. In such cases the referee is the sole judge and makes the final decision accordingly.

ACTIVE INVOLVEMENT
A player becomes "actively involved" in the play only when he is in the "area of active play." This area shifts, widens, narrows, lengthens, or shortens, according to where the ball is going and who is "involved." Involvement includes playing the ball or preventing others from having a fair play at the ball. Active involvement can occur without the ball being directly nearby. There are three elements in "active involvement." They are "interfering with an opponent," "interfering with play," and "gaining an advantage."


INTERFERING WITH AN OPPONENT
"Interfering with an opponent" means preventing an opponent from moving towards the ball. Interference can also include active physical or verbal distraction of the goalkeeper by an opponent.

INTERFERING WITH PLAY
"Interfering with play" means playing the ball.
The referee should only decide that a player is interfering with play or with an opponent if that player - in the opinion of the referee, not in the opinion of the opponents - truly interferes with play or with an opponent in the area of active play. If so, then he should be call offside. Mere presence anywhere on the field should not be considered a distraction for the opponents.

GAINING AN ADVANTAGE
"Gaining an advantage" means being near enough to play to capitalize immediately on a defender's mistake, having gained the advantage solely by being in an offside position.

MAKING THE OFFSIDE DECISION
The referee should not signal simply because a player is in an offside position, but should look for active involvement. Furthermore, if a referee is in any doubt as to whether a player is actively involved or not, he should decide in favor of the attacker; in other words, he should refrain from signaling offside.

LEAVING THE FIELD TO AVOID OFFSIDE
If a player on the attacking side moves a little way beyond the boundary of the field of play to clearly show the referee that he is not interfering with play, he does not infringe the Laws. However, if the referee considers that such a movement has a tactical aim or is in any way a feint, and the player takes part in the game immediately, after, the referee may deem his conduct to be unsporting behavior and caution him (yellow card). Play should be restarted in accordance with the Laws of the Game.

RETURNING TO THE FIELD TO PLAY THE BALL
If an attacking player passes beyond the boundary line for a moment in order to avoid an offside but then re-enters the field of play and joins in the game and plays the ball that has been passed to him by a teammate, he should be penalized for offside. His momentary departure from the field of play is not considered as leaving the field without the referee's permission and does not warrant a caution.

PUTTING AN OPPONENT IN AN OFFSIDE POSITION UNFAIRLY
If a defending player moves beyond his own goal line or across a touchline to place an opponent in an offside position, the referee should not stop play immediately to caution the defending player, but should allow play to continue. The attacker should not be punished for the position in which he has been unfairly placed; however, the referee should caution the defending player for unsporting behavior at the next stoppage of play.

DEFENDER LEGALLY OFF THE FIELD OF PLAY
A defender who leaves the field during the course of play and does not immediately return must still be considered in determining where the second to last defender is for the purpose of judging which attackers are in an offside position. Such a defender is considered to be on the touch line or goal line closest to his off-field position. a defender who leaves the field with referee's permission (and who thus requires the referee's permission to return) is not included in determining offside position.

OPPOSING ATTACKER ENTERS THE GOAL
If a forward in an offside position enters the goal and one of his teammates kicks the ball into the goal, the goal is valid and the forward should not be punished if he remains stationary and does not interfere with the opponents as the ball enters the goal. If the forward moves or shouts as the ball enters the goal, and the referee believes this contributed to the scoring of the goal, the goal would not be valid and the forward should be cautioned for unsporting behavior. In this case, the forward would be punished for misconduct, not for offside, and the restart would be a dropped ball in accordance with the special circumstances of Law VIII, as the forward was off the field of play.

LOCATION OF THE RESTART FOR OFFSIDE
As noted above, offside is punished where the infringement occurred. In other words, the indirect free kick should be taken from the place where the offside player was when his teammate played the ball. The kick should not be taken from the place where the second-to-last defender was. If the player being penalized for offside was legally off the field when his teammate last played the ball, the restart will be taken from the point on the touch line where the player re-entered the field.

WHEN IS A PLAYER IN AN OFFSIDE POSITION AT THE HALFWAY LINE?
Keeping in mind the requirement for active involvement in play, here are some guidelines for judging offside position at the halfway line.

1. If the player's toes are on the halfway line, but not over the line, there would be no offside.

2. If the player's feet are on the halfway line, with the toes over the line (heels on his own side), there could be offside (if there is active involvement).

3. If the player has one foot over the line and one foot completely on his own side, there could be offside (if there is active involvement).

4. If the player has both feet on his own side of the line, but his hands extend over the line, there would be no offside. (It would not be justifiable to count the hands, as the player can not legally play the ball with their arms or hands.)

BECOMING "ON-SIDE"
A player who is in an offside position at the moment the ball is played by a teammate can become "on-side" in only four ways: (1) The player is not in front of the ball when it is next played by one of his team; (2) the positions of the opponents change so the player is no longer in an offside position when the ball is next played by one of this team; (3) an opponent intentionally plays or gains possession of the ball; and (4) the ball goes out of play. The key point for all of these, other than the obvious case (4), that someone other than the player in the offside position has to play the ball; he cannot put himself "on-side."