Aydın Tiryaki and Gemini AI (2026)

The offside rule (IFAB Law 11) is arguably the most debated yet geometrically precise rule in football. It defines the tactical depth of the game, designed primarily to prevent attacking players from waiting near the opponent’s goal (goal-hanging) and to encourage the game to be played over a wider area rather than being compressed into one zone.

Here is the technical analysis and application details of the offside rule:

1. What is an Offside Position?

Being in an offside “position” is not in itself an offence. For an offence to occur, active involvement is required. A player is in an offside position if three conditions are met simultaneously:

• Half of the Field: The player is in the opponents’ half of the field.
• Ball Position: The player is nearer to the opponents’ goal line than the ball.
• Opponents: The player is nearer to the opponents’ goal line than the second-last opponent (usually the goalkeeper + one defender).

Important Note: The hands and arms of all players, including the goalkeepers, are not considered. For the purposes of determining offside, the upper boundary of the arm is in line with the bottom of the armpit. This is because goals can be scored with the head, body, or feet, but not the arms.

2. The Offence (Active Offside)

A player in an offside position at the moment the ball is played or touched by a teammate is only penalised on becoming involved in active play by:

• Interfering with Play: Playing or touching the ball passed or touched by a teammate.
• Interfering with an Opponent:
  • Preventing an opponent from playing or being able to play the ball by clearly obstructing the opponent’s line of vision.
  • Challenging an opponent for the ball.
  • Clearly attempting to play a ball which is close when this action impacts an opponent.
  • Making an obvious action which clearly impacts on the ability of an opponent to play the ball.
• Gaining an Advantage: Playing the ball or interfering with an opponent when it has rebound or been deflected off the goalpost, crossbar, or an opponent.

3. The Concept of “Passive Offside”

Even if a player is in an offside position, if they are not involved in the flow of the game (i.e., not touching the ball or influencing an opponent), play continues. This is commonly referred to as “passive offside.”

Example: If an attacking player waits in an offside position while a teammate passes the ball to another teammate on the opposite wing who is onside, the player in the offside position is not penalised.

4. Deliberate Play vs. Deflection

One of the most critical aspects of interpreting offside is the intent of the defending player:

• Deliberate Play: If a defending player deliberately plays the ball (except for a deliberate save) and it goes to an opponent in an offside position, the offside is negated, and play continues.
• Deflection/Rebound: If the ball merely deflects or rebounds off a defender (or is a save by the goalkeeper), the attacker in the offside position is still considered offside.

5. No Offence (Exceptions)

There is no offside offence if a player receives the ball directly from:

• A goal kick,
• A throw-in,
• A corner kick.

6. Technology and Measurement

Today, with Semi-Automated Offside Technology (SAOT) and VAR (Video Assistant Referee), offside is measured with millimetric precision. Differences involving the shoulder or toe, which the human eye cannot catch, are detected through 3D modeling to ensure fair administration of the game.

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A Note on Methods and Tools: All observations, ideas, and solution proposals in this study are the author’s own. AI was utilized as an information source for researching and compiling relevant topics strictly based on the author’s inquiries, requests, and directions; additionally, it provided writing assistance during the drafting process. (The research-based compilation and English writing process of this text were supported by AI as a specialized assistant.)